Batteries comprising alkali-transition metal phosphates and preferred electrolytes

ABSTRACT

Lithium batteries comprising:  
     (a) an electrode comprising a material of the formula  
     A a M b (XY 4 ) c Z d ,  
     wherein  
     (i) A is an alkaline metal and 0&lt;a≦9;  
     (ii) M comprises a transition metal, and 1≦b≦3;  
     (iii) XY 4  is X′O 4-x Y′ x , X′O 4-y Y′ 2y , X″S 4 , or mixtures thereof, where X′ is P, As, Sb, Si, Ge, V, S, or mixtures thereof; X″ is P, As, Sb, Si, Ge, V, or mixtures thereof; Y′ is halogen, S, N, or mixtures thereof; 0≦x&lt;3; and 0&lt;y≦2; and 0&lt;c≦3; and  
     (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and  
     (b) a counter-electrode; and  
     (c) an electrolyte comprising an alkyl and/or alkylene carbonate and a cyclic ester.  
     Preferably, M additionally comprises at least one non-transition metal. Preferred embodiments include those having an olivine structure, where c=1, and those having a NASICON structure, where c=3.

FIELD OF THE INVENTION

[0001] This invention relates to batteries. In particular, thisinvention relates to batteries comprising active materials comprisinglithium or other alkali metals, transition metals, and phosphates orsimilar moieties, with electrolytes comprising alkylene carbonates andcyclic esters.

BACKGROUND OF THE INVENTION

[0002] A wide variety of electrochemical cells, or “batteries,” is knownin the art. In general, batteries are devices that convert chemicalenergy into electrical energy, by means of an electrochemicaloxidation-reduction reaction. Batteries are used in a wide variety ofapplications, particularly as a power source for devices that cannotpracticably be powered by centralized power generation sources (e.g., bycommercial power plants using utility transmission lines).

[0003] Batteries can be generally described as comprising threecomponents: an anode that contains a material that is oxidized (yieldselectrons) during discharge of the battery (i.e., while it is providingpower); a cathode that contains a material that is reduced (acceptselectrons) during discharge of the battery; and an electrolyte thatprovides for transfer of ions between the cathode and anode. Duringdischarge, the anode is the negative pole of the battery, and thecathode is the positive pole. Batteries can be more specificallycharacterized by the specific materials that make up each of these threecomponents. Selection of these components can yield batteries havingspecific voltage and discharge characteristics that can be optimized forparticular applications.

[0004] Batteries can also be generally categorized as being “primary,”where the electrochemical reaction is essentially irreversible, so thatthe battery becomes unusable once discharged; and “secondary,” where theelectrochemical reaction is, at least in part, reversible so that thebattery can be “recharged” and used more than once. Secondary batteriesare increasingly used in many applications, because of their convenience(particularly in applications where replacing batteries can bedifficult), reduced cost (by reducing the need for replacement), andenvironmental benefits (by reducing the waste from battery disposal).

[0005] There are a variety of secondary battery systems known in theart. Among the most common systems are lead-acid, nickel-cadmium,nickel-zinc, nickel-iron, silver oxide, nickel metal hydride,rechargeable zinc-manganese dioxide, zinc-bromide, metal-air, andlithium batteries. Systems containing lithium and sodium afford manypotential benefits, because these metals are light in weight, whilepossessing high standard potentials. For a variety of reasons, lithiumbatteries are, in particular, commercially attractive because of theirhigh energy density, higher cell voltages, and long shelf-life.

[0006] Lithium batteries are prepared from one or more lithiumelectrochemical cells containing electrochemically active(electroactive) materials. Among such batteries are those havingmetallic lithium anodes and metal chalcogenide (oxide) cathodes,typically referred to as “lithium metal” batteries. The electrolytetypically comprises a salt of lithium dissolved in one or more solvents,typically nonaqueous aprotic organic solvents. Other electrolytes aresolid electrolytes (typically polymeric matrixes) that contain an ionicconductive medium (typically a lithium containing salt dissolved inorganic solvents) in combination with a polymer that itself may beionically conductive but electrically insulating.

[0007] Cells having a metallic lithium anode and metal chalcogenidecathode are charged in an initial condition. During discharge, lithiummetal yields electrons to an external electrical circuit at the anode.Positively charged ions are created that pass through the electrolyte tothe electrochemically active (electroactive) material of the cathode.The electrons from the anode pass through the external circuit, poweringthe device, and return to the cathode.

[0008] Another lithium battery uses an “insertion anode” rather thanlithium metal, and is typically referred to as a “lithium ion” battery.Insertion or “intercalation” electrodes contain materials having alattice structure into which an ion can be inserted and subsequentlyextracted. Rather than chemically altering the intercalation material,the ions slightly expand the internal lattice lengths of the compoundwithout extensive bond breakage or atomic reorganization. Insertionanodes contain, for example, lithium metal chalcogenide, lithium metaloxide, or carbon materials such as coke and graphite. These negativeelectrodes are used with lithium-containing insertion cathodes. In theirinitial condition, the cells are not charged, since the anode does notcontain a source of cations. Thus, before use, such cells must becharged in order to transfer cations (lithium) to the anode from thecathode. During discharge the lithium is then transferred from the anodeback to the cathode. During subsequent recharge, the lithium is againtransferred back to the anode where it reinserts. This back-and-forthtransport of lithium ions (Li+) between the anode and cathode duringcharge and discharge cycles had led to these cells as being called“rocking chair” batteries.

[0009] A variety of materials have been suggested for use as cathodeactive materials in lithium batteries. Such materials include, forexample, MoS₂, MnO₂, TiS₂, NbSe₃, LiCoO₂, LiNiO₂, LiMn₂O₄, V₆O₁₃, V₂O₅,SO₂, CuCl₂. Transition metal oxides, such as those of the generalformula Li_(x)M₂O_(y), are among those materials preferred in suchbatteries having intercalation electrodes. Other materials includelithium transition metal phosphates, such as LiFePO₄, and Li₃V₂(PO₄)₃.Such materials having structures similar to olivine or NASICON materialsare among those known in the art. Cathode active materials among thoseknown in the art are disclosed in S. Hossain, “Rechargeable LithiumBatteries (Ambient Temperature),” Handbook of Batteries, 2d ed., Chapter36, Mc-Graw Hill (1995); U.S. Pat. No. 4,194,062, Carides, et al.,issued Mar. 18, 1980; U.S. Pat. No. 4,464,447, Lazzari, et al., issuedAug. 7, 1984; U.S. Pat. No. 5,028,500, Fong et al., issued Jul. 2, 1991;U.S. Pat. No. 5,130,211, Wilkinson, et al., issued Jul. 14, 1992; U.S.Pat. No. 5,418,090, Koksbang et al., issued May 23, 1995; U.S. Pat. No.5,514,490, Chen et al., issued May 7, 1996; U.S. Pat. No. 5,538,814,Kamauchi et al., issued Jul. 23, 1996; U.S. Pat. No. 5,695,893, Arai, etal., issued Dec. 9, 1997; U.S. Pat. No. 5,804,335, Kamauchi, et al.,issued Sep. 8, 1998; U.S. Pat. No. 5,871,866, Barker et al., issued Feb.16, 1999; U.S. Pat. No. 5,910,382, Goodenough, et al., issued Jun. 8,1999; PCT Publication WO/00/31812, Barker, et al., published Jun. 2,2000; PCT Publication WO/00/57505, Barker, published Sep. 28, 2000; U.S.Pat. No. 6,136,472, Barker et al., issued Oct. 24, 2000; U.S. Pat. No.6,153,333, Barker, issued Nov. 28, 2000; European Patent Publication1,049,182, Ravet et al., published Nov. 2, 2000; PCT PublicationWO/01/13443, Barker, published Feb. 22, 2001; PCT PublicationWO/01/54212, Barker et al., published Jul. 26, 2001; PCT PublicationWO/01/84655, Barker et al., published Nov. 8, 2001.

[0010] Preferably, such a cathode material exhibits a high free energyof reaction with lithium, is able to release and insert a large quantityof lithium, maintains its lattice structure upon insertion andextraction of lithium, allows rapid diffusion of lithium, affords goodelectrical conductivity, is not significantly soluble in the electrolytesystem of the battery, and is readily and economically produced.However, many of the cathode materials known in the art lack one or moreof these characteristics. As a result, for example, many such materialsare not economical to produce, afford insufficient voltage, haveinsufficient charge capacity, or lose their ability to be recharged overmultiple cycles.

SUMMARY OF THE INVENTION

[0011] The invention provides batteries comprising active materialscomprising lithium or other alkali metals, transition metals andoptionally other metals, and a phosphate, substituted phosphate orsimilar moiety. In particular, the present invention provides a lithiumbattery comprising

[0012] (a) a first electrode comprising an active material of theformula

A_(a)M_(b)(XY₄)_(c)Z_(d,)

[0013] wherein

[0014] (i) A is selected from the group consisting of Li, Na, K, andmixtures thereof, and 0<a ≦9;

[0015] (ii) M is one or more metals, comprising at least one metal whichis capable of undergoing oxidation to a higher valence state, and 1≦b≦3;

[0016] (iii) XY₄ is selected from the group consisting ofX′O_(4-x)Y′_(x), X′O_(4-y) _(Y′) _(2y), X″S₄, and mixtures thereof,where X′ is selected from the group consisting of P, As, Sb, Si, Ge, V,S, and mixtures thereof; X″ is selected from the group consisting of P,As, Sb, Si, Ge, V and mixtures thereof; Y′ is selected from the groupconsisting of halogen, S, N, and mixtures thereof; 0≦x<3; and 0<y≦2; and0<c≦3;

[0017] (iv) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and

[0018] wherein M, XY₄, Z, a, b, c, d, x and y are selected so as tomaintain electroneutrality of said compound;

[0019] (b) a second electrode which is a counter-electrode to said firstelectrode; and

[0020] (c) an electrolyte comprising a mixture of a cyclic ester and acarbonate selected from the group consisting of alkyl carbonates,alkylene carbonates, and mixtures thereof.

[0021] In a preferred embodiment, M comprises two or more transitionmetals from Groups 4 to 11 of the Periodic Table. In another preferredembodiment, M comprises M′M″, where M′ is at least one transition metalfrom Groups 4 to 11 of the Periodic Table; and M″ is at least oneelement from Groups 2, 3, and 12-16 of the Periodic Table. Preferredembodiments include those where c=1, those where c=2, and those wherec=3. Preferred embodiments include those where a≦1 and c=1, those wherea=2 and c=1, and those where a≧3 and c=3. Preferred embodiments alsoinclude those having a structure similar to the mineral olivine (herein“olivines”), and those having a structure similar to NASICON (NA SuperIonic CONductor) materials (herein “NASICONs”). In a particularlypreferred embodiment, M comprises Co_(e)Fe_(f)M¹ _(g)M² _(h)M³ _(i),where M¹ is at least one transition metal from Groups 4 to 11 of thePeriodic Table; M² comprises one or more +2 oxidation statenon-transition metals, and M³ comprises one or more +3 oxidation statenon-transition metals, and e+f+g=b. In such an embodiment, preferably Acomprises Li, 0.8≦a≦1.2, 0.8≦b≦1.5, and c=1. As used herein, unlessotherwise specified, a variable described algebraically as equal to(“=”), less than or equal to (“≦”), or greater than or equal to (“≧”) anumber is intended to subsume values or ranges of values about equal orfunctionally equivalent to said number.

[0022] It has been found that the novel batteries of this inventionafford benefits over such materials and devices among those known in theart. Such benefits include one or more of increased capacity, enhancedcycling capability, enhanced reversibility, and reduced costs. Specificbenefits and embodiments of the present invention are apparent from thedetailed description set forth herein. It should be understood, however,that the detailed description and specific examples, while indicatingembodiments among those preferred, are intended for purposes ofillustration only and are not intended to limited the scope of theinvention.

DESCRIPTION OF THE INVENTION

[0023] The present invention provides batteries comprising certainelectrode active materials and electrolytes. As used herein, “battery”refers to a device comprising one or more electrochemical cells for theproduction of electricity. Each electrochemical cell comprises an anode,a cathode, and an electrolyte. Two or more electrochemical cells may becombined, or “stacked,” so as to create a multi-cell battery having avoltage that is the sum of the voltages of the individual cells.

[0024] The electrode active materials of this invention may be used inthe anode, the cathode, or both. Preferably, the active materials ofthis invention are used in the cathode. (As used herein, the terms“anode” and “cathode” refer to the electrodes at which oxidation andreduction occur, respectively, during battery discharge. During chargingof the battery, the sites of oxidation and reduction are reversed. Also,as used herein, the words “preferred” and “preferably” refer toembodiments of the invention that afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful and is not intended to exclude other embodiments from the scopeof the invention.)

[0025] Electrode Active Materials:

[0026] The present invention provides active materials (herein“electrode active materials”) comprising lithium or other alkali metals,a transition metal, a phosphate or similar moiety, and (optionally) ahalogen or hydroxyl moiety. Such electrode active materials includethose of the formula A_(a)M_(b)(XY₄)_(c)Z_(d). (As used herein, the word“include,” and its variants, is intended to be non-limiting, such thatrecitation of items in a list is not to the exclusion of other likeitems that may also be useful in the materials, compositions, devices,and methods of this invention.)

[0027] A is selected from the group consisting of Li (lithium), Na(sodium), K (potassium), and mixtures thereof. In a preferredembodiment, A is Li, a mixture of Li with Na, a mixture of Li with K, ora mixture of Li, Na and K. In another preferred embodiment, A is Na, ora mixture of Na with K. Preferably “a” is from about 0.1 to about 6,more preferably from about 0.2 to about 6. Where c=1, a is preferablyfrom about 0.1 to about 3, preferably from about 0.2 to about 2. In apreferred embodiment, where c=1, a is less than about 1. In anotherpreferred embodiment, where c=1, a is about 2. Preferably “a” is fromabout 0.8 to about 1.2. Where c=2, a is preferably from about 0.1 toabout 6, preferably from about 1 to about 6. Where c=3, a is preferablyfrom about 0.1 to about 6, preferably from about 2 to about 6,preferably from about 3 to about 6. In another embodiment, “a” ispreferably from about 0.2 to about 1.0.

[0028] In a preferred embodiment, removal of alkali metal from theelectrode active material is accompanied by a change in oxidation stateof at least one of the metals comprising M. The amount of said metalthat is available for oxidation in the electrode active materialdetermines the amount of alkali metal that may be removed. Such conceptsare, in general application, well known in the art, e.g., as disclosedin U.S. Pat. No. 4,477,541, Fraioli, issued Oct. 16, 1984; and U.S. Pat.No. 6,136,472, Barker, et al., issued Oct. 24, 2000, both of which areincorporated by reference herein.

[0029] Referring to the general formula A_(a)M_(b)(XY₄)_(c)Z_(d), theamount (a′) of alkali metal that can be removed, as a function of thequantity of (b′) and valence state (V^(M)) of oxidizable metal (M), is

a′=b′(ΔV^(M)),

[0030] where ΔV^(M) is the difference between the valence state of themetal in the active material and a valence state readily available forthe metal. (The term oxidation state and valence state are used in theart interchangeably.) For example, for an active material comprisingiron (Fe) in the +2 oxidation state, ΔV^(M)=1, wherein iron may beoxidized to the +3 oxidation state (although iron may also be oxidizedto a +4 oxidation state in some circumstances). If b=1 (one atomic unitof Fe per atomic unit of material), the maximum amount (a′) of alkalimetal (oxidation state +1) that can be removed during cycling of thebattery is 1 (one atomic units of alkali metal). If b=1.25, the maximumamount of (a′) of alkali metal that can be removed during cycling of thebattery is 1.25.

[0031] In general, the value of “a” in the active materials can varyover a wide range. In a preferred embodiment, active materials aresynthesized for use in preparing a lithium ion battery in a dischargedstate. Such active materials are characterized by a relatively highvalue of “a”, with a correspondingly low oxidation state of M of theactive material. As the battery is charged from its initial unchargedstate, an amount a′ of lithium is removed from the active material asdescribed above. The resulting structure, containing less lithium (i.e.,a−a′) than in the as-prepared state as well as the transition metal in ahigher oxidation state than in the as-prepared state, is characterizedby lower values of a, while essentially maintaining the original valueof b. The active materials of this invention include such materials intheir nascent state (i.e., as manufactured prior to inclusion in anelectrode) and materials formed during operation of the battery (i.e.,by insertion or removal of Li or other alkaline metal).

[0032] The value of “b” and the total valence of M in the activematerial must be such that the resulting active material is electricallyneutral (i.e., the positive charges of all cationic species in thematerial balance the negative charges of all anionic species), asfurther discussed below. The net valence of M (V^(M)) having a mixtureof elements (M1, M2 . . . Mt) may be represented by the formula

V ^(M) =V ^(M1) b ₁ +V ^(M2) b ₂ + . . . V ^(Mt) b _(t),

[0033] where b₁+b₂+ . . . b_(t)=1, and V^(M1) is the oxidation state ofM1, V^(M2) is the oxidation state of M2, etc. (The net valence of M andother components of the electrode active material is discussed further,below.)

[0034] M is one or more metals including at least one metal that iscapable of undergoing oxidation to a higher valence state (e.g.,Co⁺²→Co⁺³), preferably a transition metal selected from Groups 4-11 ofthe Periodic Table. As referred to herein, “Group” refers to the Groupnumbers (i.e., columns) of the Periodic Table as defined in the currentIUPAC Periodic Table. See, e.g., U.S. Pat. No. 6,136,472, Barker et al.,issued Oct. 24, 2000, incorporated by reference herein. In anotherpreferred embodiment, M further comprises a non-transition metalselected from Groups 2, 3, and 12-16 of the Periodic Table.

[0035] In another preferred embodiment, preferably where c=1, Mcomprises Co_(e),Fe_(f)M¹ _(g)M² _(h)M³ _(i), wherein M¹ is at least onetransition metal from Groups 4 to 11, M² is at least one +2 oxidationstate non-transition metal, M³ is at least one +3 oxidation state nontransition metal, e≧0, f≧0, g≧0, h≧0, i≧0 and (e+f+g+h+i)=b. Preferably,at least one of e and f are greater than zero, more preferably both. Ina preferred embodiment 0<(e+f+g+h+i)≦2, more preferably 0.8≦(e+f+g)≦1.2,and even more preferably 0.9≦(e+f+g)≦1.0. Preferably, e≧0.5, morepreferably e≧0.8. Preferably, 0.01≦f≦0.5, more preferably 0.05≦f≦0.15.Preferably, 0.01≦g≦0.5, more preferably 0.05≦g≦0.2. In a preferredembodiment, (h+i)>1, preferably 0.01≦(h+i)≦0.5, and even more preferably0.01≦(h+i)≦0.1. Preferably, 0.01≦h≦0.2, more preferably 0.01≦h≦0.1.Preferably 0.01≦i≦0.2, more preferably 0.01≦i≦0.1.

[0036] Transition metals useful herein include those selected from thegroup consisting of Ti (Titanium), V (Vanadium), Cr (Chromium), Mn(Manganese), Fe (Iron), Co (Cobalt), Ni (Nickel), Cu (Copper), Zr(Zirconium), Nb (Niobium), Mo (Molybdenum), Ru (Ruthenium), Rh(Rhodium), Pd (Palladium), Ag (Silver), Cd (Cadmium), Hf (Hafnium), Ta(Tantalum), W (Tungsten), Re (Rhenium), Os (Osmium), Ir (Iridium), Pt(Platinum), Au (Gold), Hg (Mercury), and mixtures thereof. Preferred arethe first row transition series (the 4th Period of the Periodic Table),selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, andmixtures thereof. Particularly preferred transition metals include thoseselected from the group consisting of Fe, Co, Ti, Mn, and mixturesthereof. In a preferred embodiment, M is Co_(1-m)Fe_(m), where 0<m≦0.5.Preferably 0.01<m≦0.2. Although, a variety of oxidation states for suchtransition metals are available, in some embodiments it is mostpreferable that the transition metals have a +2 oxidation state. As usedherein, the recitation of a genus of elements, materials or othercomponents, from which an individual component or mixture of componentscan be selected, is intended to include all possible sub-genericcombinations of the listed components, and mixtures thereof.

[0037] In a preferred embodiment, M further comprises one or morenon-transition metals. As referred to herein, “non-transition metals”include metals and metalloids from Groups 2, 3, and 12-16 of thePeriodic Table that are capable of forming stable active materials anddo not significantly impede the insertion or removal of lithium or otheralkaline metals from the active materials under normal operatingconditions. Preferably, such elements do not include C (carbon), Si(silicon), N (nitrogen) and P (phosphorus). Preferred non-transitionmetals include those not readily capable of undergoing oxidation to ahigher valence state in the electrode active material under normaloperating conditions. Among the non-transition metals useful herein arethose selected from the group consisting of Group 2 elements,particularly Be (Beryllium), Mg (Magnesium), Ca (Calcium), Sr(Strontium), Ba (Barium); Group 3 elements, particularly Sc (Scandium),Y (Yttrium), and the lanthamides, particularly La (Lanthanum), Ce(Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium); Group 12elements, particularly Zn (zinc) and Cd (cadmium); Group 13 elements,particularly B (Boron), Al (Aluminum), Ga (Gallium), In (Indium), Tl(Thallium); Group 14 elements, particularly Si (Silicon), Ge(Germanium), Sn (Tin), and Pb (Lead); Group 15 elements, particularly As(Arsenic), Sb (Antimony), and Bi (Bismuth); Group 16 elements,particularly Te (Tellurium); and mixtures thereof. Preferrednon-transition metals include the Group 2 elements, Group 12 elements,Group 13 elements, and Group 14 elements. Particularly preferrednon-transition metals include those selected from the group consistingof Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, and mixtures thereof.Particularly preferred are non-transition metals selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof.

[0038] As further discussed herein, “b” is selected so as to maintainelectroneutrality of the electrode active material. In a preferredembodiment, where c=1, b is from about 1 to about 2, preferably about 1.In another preferred embodiment, where c=2, b is from about 2 to about3, preferably about 2.

[0039] XY₄ is an anion, preferably selected from the group consisting ofX′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′is selected from the group consisting of P (phosphorus), As (arsenic),Sb (antimony), Si (silicon), Ge (germanium), V (vanadium) S (sulfur),and mixtures thereof; X″ is selected from the group consisting of P, As,Sb, Si, Ge, V, and mixtures thereof. XY₄ anions useful herein includephosphate, silicate, germanate, vanadate, arsenate, antimonate, sulfuranalogs thereof, and mixtures thereof. In a preferred embodiment, X′ andX″ are each selected from the group consisting of P, Si, and mixturesthereof. In a particularly preferred embodiment, X′ and X″ are P.

[0040] Y′ is selected from the group consisting of halogen, S, N, andmixtures thereof. Preferably Y′ is F (fluorine).In a preferredembodiment 0≦x≦3; and 0<y≦2, such that a portion of the oxygen (O) inthe XY₄ moiety is substituted with halogen. In another preferredembodiment, x and y are 0. In a particularly preferred embodiment XY₄ isX′O₄, where X′ is preferably P or Si, more preferably P. In anotherparticularly preferred embodiment, XY₄ is PO_(4-x)Y′_(x), where Y′ ishalogen and 0<x≦1. Preferably 0.01≦x≦0.05, more preferably 0.02≦x≦0.03.

[0041] In a preferred embodiment, XY₄ is PO₄ (a phosphate group) or amixture of PO₄ with another XY₄ group (i.e., where X′ is not P, Y′ isnot O, or both, as defined above). When part of the phosphate group issubstituted, it is preferred that the substitute group be present in aminor amount relative to the phosphate. In a preferred embodiment, XY₄comprises 80% or more phosphate and up to about 20% of one or morephosphate substitutes. Phosphate substitutes include, withoutlimitation, silicate, sulfate, antimonate, germanate, arsenate,monofluoromonophosphate, difluoromonophosphate, sulfur analogs thereof,and combinations thereof. Preferably, XY₄ comprises a maximum of about10% of a phosphate substitute or substitutes. (The percentages are basedon mole percent.) Preferred XY₄ groups include those of the formula(PO₄)_(1-k)(B)_(k), where B represents an XY₄ group or combination ofXY₄ groups other than phosphate, and k≦0.5. Preferably, k≦0.8, morepreferably less than about k≦0.2, more preferably k≦0.1.

[0042] Z is OH, halogen, or mixtures thereof. In a preferred embodiment,Z is selected from the group consisting of OH (hydroxyl), F (fluorine),Cl (chlorine), Br (bromine) and mixtures thereof. In a preferredembodiment, Z is OH. In another preferred embodiment, Z is F, ormixtures of F with OH, Cl, or Br. In one preferred embodiment, d=0. Inanother preferred embodiment, d>0, preferably from about 0.1 to about 6,more preferably from about 0.2 to about 6. In such embodiments, wherec=1, d is preferably from about 0.1 to about 3, preferably from about0.2 to about 2. In a preferred embodiment, where c=1, d is about 1.Where c=2, d is preferably from about 0.1 to about 6, preferably fromabout 1 to about 6. Where c=3, d is preferably from about 0.1 to about6, preferably from about 2 to about 6, preferably from about 3 to about6.

[0043] The composition of M, XY₄, Z and the values of a, b, c, d, x, andy are selected so as to maintain electroneutrality of the electrodeactive material. As referred to herein “electroneutrality” is the stateof the electrode active material wherein the sum of the positivelycharged species (e.g., A and M) in the material is equal to the sum ofthe negatively charged species (e.g., XY₄) in the material. Preferably,the XY₄ moieties are comprised to be, as a unit moiety, an anion havinga charge of −2, −3, or −4, depending on the selection of X′, X″, Y′, andx and y. When XY₄ is a mixture of groups such as the preferredphosphate/phosphate substitutes discussed above, the net charge on theXY₄ anion may take on non-integer values, depending on the charge andcomposition of the individual groups XY₄ in the mixture.

[0044] In general, the valence state of each component element of theelectrode active material may be determined in reference to thecomposition and valence state of the other component elements of thematerial. By reference to the general formula A_(a)M_(b)(XY₄)_(c)Z_(d),the electroneutrality of the material may be determined using theformula

(V ^(A))a+(V ^(M))b+(V ^(X))c=(V ^(Y))4c+(V ^(Z))d

[0045] where V^(A) is the net valence of A, V^(M) is the net valence ofM, V^(Y) is the net valence of Y, and V^(Z) is the net valence of Z. Asreferred to herein, the “net valence” of a component is (a) the valencestate for a component having a single element which occurs in the activematerial in a single valence state; or (b) the mole-weighted sum of thevalence states of all elements in a component comprising more than oneelement, or comprising a single element having more than one valencestate. The net valence of each component is represented in the followingformulae.

(V ^(A))b=[(V ^(A1))a ¹+(Va1 ^(A2))a ²+ . . . (V ^(An))a ^(n) ]/n; a ¹+a ² + . . . a ^(n) =a

(V ^(M))b=[(V ^(M1))b ¹+(V ^(M2))b ²+ . . . (V ^(Mn))b ^(n) ]/n; b ¹ +b² + . . . b ^(n) =b

(V ^(X))c=[(V ^(X1))c ¹+(V ^(X2))c ²+ . . . (V ^(Xn))c ^(n) ]/n; c ¹ +c² + . . . c ^(n) =c

(V ^(Y))c=[(V ^(Y1))c ¹+(V ^(Y2))c ²+ . . . (V ^(Yn))c ^(n) ]/n; c ¹ +c² + . . . c ^(n) =c

(V ^(Z))d=[(V ^(Z1))d ¹+(V ^(Z2))d ²+ . . . (V ^(Zn))d ^(n) ]/n; d ¹ +d² + . . . d ^(n) =d

[0046] In general, the quantity and composition of M is selected giventhe valency of X, the value of “c,” and the amount of A, so long as Mcomprises at least one metal that is capable of oxidation. Thecalculation for the valence of M can be simplified, where V^(A)=1,V^(Z)=1, as follows.

[0047] For compounds where c=1: (V^(M))b=(V^(Y))4+d−a−(V^(X))

[0048] For compounds where c=3: (V^(M))b=(V^(Y))12+d−a−(V^(X))3

[0049] The values of a, b, c, d, x, and y may result in stoichiometricor non-stoichiometric formulas for the electrode active materials. In apreferred embodiment, the values of a, b, c, d, x, and y are all integervalues, resulting in a stoichiometric formula. In another preferredembodiment, one or more of a, b, c, d, x and y may have non-integervalues. It is understood, however, in embodiments having a latticestructure comprising multiple units of a non-stoichiometric formulaA_(a)M_(b)(XY₄)_(c)Z_(d), that the formula may be stoichiometric whenlooking at a multiple of the unit. That is, for a unit formula where oneor more of a, b, c, d, x, or y is a non-integer, the values of eachvariable become an integer value with respect to a number of units thatis the least common multiplier of each of a, b, c, d, x and y. Forexample, the active material Li₂Fe_(0.5)Mg_(0.5)PO₄F isnon-stoichiometric. However, in a material comprising two of such unitsin a lattice structure, the formula is Li₄FeMg(PO₄)₂F₂.

[0050] A preferred electrode active material embodiment comprises acompound of the formula

Li_(a)M_(b)(PO₄)Z_(d),

[0051] wherein

[0052] (a) 0.1<a≦4;

[0053] (b) M is M′_(1-m)M″_(m), where M′ is at least one transitionmetal from Groups 4 to 11 of the Periodic Table; M″ is at least onenon-transition metal from Groups 2, 3, and 12-16 of the Periodic Table,0<m<1, and 1≦b≦3; and

[0054] (c) Z comprises halogen, and 0≦d≦4; and

[0055] wherein M, Z, a, b, and d are selected so as to maintainelectroneutrality of said compound. Preferably, M′ is selected from thegroup consisting of Fe, Co, Ni, Mn, Cu, V, Zr, Ti, Cr, and mixturesthereof; more preferably M′ is selected from the group consisting of Fe,Co, Mn, Cu, V, Cr, and mixtures thereof. Preferably, M″ is selected fromthe group consisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, andmixtures thereof; more preferably M″ is selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof. Preferably Zcomprises F.

[0056] Another preferred embodiment comprises a compound of the formula:

A_(a)M_(b)(XY₄)₃Z_(d),

[0057] wherein

[0058] (a) A is selected from the group consisting of Li, Na, K, andmixtures thereof, and 2≦a ≦9;

[0059] (b) M comprises one or more metals, comprising at least one metalwhich is capable of undergoing oxidation to a higher valence state, and1≦b≦3;

[0060] (c) XY₄ is selected from the group consisting of X′O_(4-x)Y′_(x),X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′ is selected fromthe group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof;X″ is selected from the group consisting of P, As, Sb, Si, Ge, V, andmixtures thereof; Y′ is selected from the group consisting of halogen,S, N, and mixtures thereof; 0≦x<3; and 0<y<4; and

[0061] (d) Z is OH, halogen, or mixtures thereof, and 0≦d≦6; and

[0062] wherein M, XY₄, Z, a, b, d, x and y are selected so as tomaintain electroneutrality of said compound. In a preferred embodiment,A comprises Li, or mixtures of Li with Na or K. In another preferredembodiment, A comprises Na, K, or mixtures thereof. In a preferredembodiment, M comprises two or more transition metals from Groups 4 to11 of the Periodic Table, preferably transition metals selected from thegroup consisting of Fe, Co, Ni, Mn, Cu, V, Zr, Ti, Cr, and mixturesthereof. In another preferred embodiment, M comprises M′_(1-m)M″_(m),where M′ is at least one transition metal from Groups 4 to 11 of thePeriodic Table; and M″ is at least one element from Groups 2, 3, and12-16 of the Periodic Table; and 0<m<1. Preferably, M′ is selected fromthe group consisting of Fe, Co, Ni, Mn, Cu, V, Zr, Ti, Cr, and mixturesthereof; more preferably M′ is selected from the group consisting of Fe,Co, Mn, Cu, V, Cr, and mixtures thereof. Preferably, M″ is selected fromthe group consisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, andmixtures thereof; more preferably, M″ is selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof. In a preferredembodiment, XY₄ is PO₄. In another preferred embodiment, X′ comprisesAs, Sb, Si, Ge, S, and mixtures thereof; X″ comprises As, Sb, Si, Ge andmixtures thereof; and 0<x<3. In a preferred embodiment, Z comprises F,or mixtures of F with Cl, Br, OH, or mixtures thereof. In anotherpreferred embodiment, Z comprises OH, or mixtures thereof with Cl or Br.

[0063] Another preferred embodiment comprises a compound of the formula

A_(a)M¹ _(e)M² _(f)M³ _(g)XY₄,

[0064] wherein

[0065] (a) A is selected from the group consisting of Li, Na, K, andmixtures thereof, and 0<a ≦2;

[0066] (b) M¹ comprises one or more transition metals, where e>0;

[0067] (c) M² comprises one or more +2 oxidation state non transitionmetals, where f>0;

[0068] (d) M³ comprises one or more +3 oxidation state non-transitionmetal, where g>0; and

[0069] (e) XY₄ is selected from the group consisting of X′O_(4-x)Y′_(x),X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′ is selected fromthe group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof;X″ is selected from the group consisting of P, As, Sb, Si, Ge, V, andmixtures thereof; Y′ is selected from the group consisting of halogen,S, N, and mixtures thereof; 0<x<3; and 0<y<2; and

[0070] wherein e+f+g<2, and M¹, M², M³, XY₄, a, e, f, g, x, and y areselected so as to maintain electroneutrality of said compound. Inembodiments where XY₄ is PO_(4-x)Y′_(x) and M¹ is a +2 oxidation statetransition metal, a +2e+2f+3g=3-x.

[0071] Preferably, e+f+g=b. In a preferred embodiment 0<(e+f+g)<2, morepreferably 0.8≦(e+f+g)≦1.5, and even more preferably 0.9≦(e+f+g)≦1,wherein 0.01≦(f+g)≦0.5, more preferably 0.05≦(f+g)≦0.2, and even morepreferably 0.05≦(f+g)≦0.1.

[0072] In a preferred embodiment, A is Li. Preferably, M¹ is at leastone transition metal from Groups 4 to 11 of the Periodic Table; M² is atleast one non-transition metal from Groups 2, 3, and 12-16 of thePeriodic Table, and M³ is a +3 oxidation state metal selected from Group13. Preferably M¹ is selected from the group consisting of Fe, Co, Ni,Mn, Cu, V, Zr, Ti, Cr, and mixtures thereof; more preferably M¹ is a +2oxidation state transition metal selected from the group consisting ofFe, Co, Mn, Cu, V, Cr, and mixtures thereof. Preferably M² is selectedfrom the group consisting +2 oxidation state non-transition metals andmixtures thereof; more preferably M² is selected from the groupconsisting of Be, Mg, Ca, Sr, Ba, Ra, Zn, Cd, Hg and mixtures thereof.Preferably, M³ is a +3 oxidation state non-transition metal, preferablyM³ is selected from Group 13, more preferably Sc, Y, La, Ac, B, Al, Ga,In, Tl and mixtures thereof. Preferably M³ is Al. Preferably 0<(f+g)<1,preferably 0.01≦(f+g)≦0.3, more preferably 0.05≦(f+g)≦0.1. Preferably,0.01≦f≦0.3, more preferably 0.05≦f≦0.1, and even more preferably0.01≦f≦0.03. Also preferably, 0.01≦g≦0.3, more preferably 0.05≦g≦0.1,and even more preferably 0.01≦g≦0.03.

[0073] Another preferred embodiment comprises a compound of the formula

Li_(a)CO_(e)Fe_(f)M¹ _(g)M² _(h)M³ _(i)XY₄

[0074] wherein

[0075] (a) 0<a≦2, e>0, and f>0;

[0076] (b) M¹ is one or more transition metals, where g≧0;

[0077] (C) M² is one or more +2 oxidation state non-transition metals,where h≧0;

[0078] (d) M³ is one or more +3 oxidation state non-transition metals,where i≧0; and

[0079] (e) XY₄ is selected from the group consisting of X′O_(4-x)Y′_(x),X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′ is selected fromthe group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof;X″ is selected from the group consisting of P, As, Sb, Si, Ge, V, andmixtures thereof; Y′ is selected from the group consisting of halogen,S, N, and mixtures thereof; 0≦x≦3; and 0<y≦2;

[0080] wherein (e+f+g+h+i)≦2, and M¹, M², M³, XY₄, a, e, f, g, h, i, x,and y are selected so as to maintain electroneutrality of said compound.Preferably, 0.8≦(e+f+g+h+i)≦1.2, more preferably 0.9≦(e+f+g+h+i)≦1.Preferably, e>0.5, more preferably, e≧0.8. Preferably, 0.01≦f≦0.5, morepreferably, 0.05≦f≦0.15. Preferably, 0.01≦g≦0.5, more preferably,0.05≦g≦0.2. Preferably M¹ is selected from the group consisting of Ti,V, Cr, Mn, Ni, Cu and mixtures thereof. Preferably, M¹ is selected fromthe group consisting of Mn, Ti, and mixtures thereof.

[0081] Preferably, (h+i)>0, more preferably 0.01≦(h+i)≦0.5, morepreferably 0.02≦(h+i)≦0.3. Preferably, 0.01≦h≦0.2, more preferably,0.01≦h≦0.1. Preferably, M² is selected from the group consisting of Be,Mg, Ca, Sr, Ba, and mixtures thereof. More preferably, M² is Mg.Preferably, 0.01≦i≦0.2, more preferably 0.01≦i≦0.1. Preferably, M³ isselected from the group consisting of B, Al, Ga, In, and mixturesthereof. More preferably, M³ is Al.

[0082] In one embodiment, XY₄ is PO₄. In another embodiment, XY₄ isPO_(4-x)F_(x), and 0<x≦1, preferably, 0.01≦x≦0.05.

[0083] Another preferred embodiment comprises a compound having anolivine structure. During charge and discharge of the battery, lithiumions are added to, and removed from, the active material preferablywithout substantial changes in the crystal structure of the material.Such materials have sites for the alkali metal (e.g., Li), thetransition metal (M), and the XY₄ (e.g., phosphate) moiety. In someembodiments, all sites of the crystal structure are occupied. In otherembodiments, some sites may be unoccupied, depending on, for example,the oxidation states of the metal (M). Among such preferred compoundsare those of the formula

LiM(PO_(4-x)Y′_(x))

[0084] wherein M is M¹ _(g)M² _(h)M³ _(i)M⁴ _(j), and

[0085] (a) M¹ is one or more transition metals;

[0086] (b) M² is one or more +2 oxidation state non-transition metals;

[0087] (c) M³ is one or more +3 oxidation state non-transition metals,

[0088] (d) M⁴ is one or more +1 oxidation state non-transition metals;and

[0089] (e) Y′ is halogen; and

[0090] g,>0; h≧0; i≧0; j≧0; (g+h+i+j)≦1; and the net valence of M is2-x. Preferably, g≧0.8, more preferably, g≧0.9. Preferably, M¹ is a +2oxidation state transition metal selected from the group consisting ofV, Cr, Mn, Fe, Co, Ni, and mixtures thereof. More preferably, M¹ isselected from the group consisting of Fe, Co, and mixtures thereof.Preferably M¹ additionally comprises Ti.

[0091] Preferably, (h+i)>0.1, more preferably, 0.02≦(h+i)≦0.5, morepreferably, 0.02≦(h+i)≦0.3. Preferably, 0.01≦h≦0.2, more preferably,0.01≦h≦0.1. Preferably, M² is selected from the group consisting of Be,Mg, Ca, Sr, Ba, and mixtures thereof. Preferably, 0.01≦i≦0.2, morepreferably, 0.01≦i≦0.1. Preferably, M³ is Al.

[0092] In one embodiment, j=0. In another embodiment, 0.01≦j≦0.1.Preferably, M4 is selected from the group consisting of Li, Na, and K.More preferably, M⁴ is Li.

[0093] In one embodiment, x=0. In another embodiment, 0<x≦1. In such anembodiment, preferably, 0.01≦x≦0.05, and (g+h+i+j)<1. In an embodimentwhere j=0, preferably, (g+h+i)=1-x.

[0094] Non-limiting examples of active materials of the inventioninclude the following: Li_(0.95)Co_(0.8)Fe_(0.15)Al_(0.05)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Cu_(0.45)Fe_(0.45)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.02)Mg_(0.05)PO₄,Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)Fe_(0.08)Mn_(0.12)A_(0.025)Mg_(0.05)PO₄,LiCo_(0.75)Fe_(0.15)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.80)Fe_(0.10)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),Li_(1.025)Co_(0.6)Fe_(0.1)Mn_(0.075)Mg_(0.025)Al_(0.05)PO₄,Li_(1.0)Na_(0.25)Co_(0.6)Fe_(0.1)Cu_(0.075)Mg_(0.025)Al_(0.05)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.075)PO₄,Li_(1.025)Co_(0.6)Fe_(0.05)Al_(0.12)Mg_(0.025)PO_(3.75)F_(0.025),Li_(1.025)Co_(0.7)Fe_(0.1)Mg_(0.025)Al_(0.04)PO_(3.75)F_(0.25),Li_(0.75)Co_(0.5)Fe_(0.025)Mn_(0.025)Ca_(0.015)Al_(0.04)PO₃F,Li_(1.025)Cu_(0.6)Fe_(0.05)B_(0.12)Ca_(0.0325)PO_(3.75)F_(0.25),Li_(1.025)Cu_(0.65)Fe_(0.05)Mg_(0.125)Al_(0.1)PO_(3.75)F_(0.25),Li_(1.025)Co_(0.65)Fe_(0.05)Mg_(0.065)Al_(0.14)PO_(3.975)F_(0.025),Li_(1.075)Co_(0.8)Fe_(0.05)Mg_(0.025)Al_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li_(0.25)Fe_(0.7)Al_(0.45)PO₄, LiMnAl_(0.067)(PO₄)_(0.8)(SiO₄)_(0.2),Li_(0.95)Cu_(0.9)Al_(0.05)Mg_(0.05)PO₄,Li_(0.95)Fe_(0.8)Ca_(0.15)Al_(0.05)PO₄,Li_(0.25)MnBe_(0.425)Ga_(0.3)SiO₄,Li_(0.5)Na_(0.25)Mn_(0.6)Ca_(0.375)Al_(0.1)PO₄,Li_(0.25)Al_(0.25)Mg_(0.25)Co_(0.75)PO₄,Na_(0.55)B_(0.15)Ni_(0.75)Ba_(0.25)PO₄,Li_(1.025)Cu_(0.9)Al_(0.025)Mg_(0.05)PO₄,K_(1.025)Ni_(0.09)Al_(0.025)Ca_(0.05)PO₄,Li_(0.95)Cu_(0.9)Al_(0.05)Mg_(0.05)PO₄,Li_(0.95)Fe_(0.8)Ca_(0.15)Al_(0.05)PO₄,Li_(0.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Cu_(0.9)Al_(1.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.025)PO₄,LiCo_(0.75)Fe_(0.15)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025)LiCo_(0.9)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li_(0.75)Co_(0.625)Al_(0.25)PO_(3.75)F_(0.25),Li_(1.075)Co_(0.8)Cu_(0.05)Mg_(0.025)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.075)Fe_(0.8)Mg_(0.075)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.075)Co_(0.8)Mg_(0.075)Al_(0.05)PO_(3.975)F_(0.025),Li_(1.025)Co_(0.8)Mg_(0.1)Al_(0.05)PO_(3.975)F_(0.025),LiCo_(0.7)Fe_(0.2)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),Li₂Fe_(0.8)Mg_(0.2)PO₄F; Li₂Fe_(0.5)Co_(0.5)PO₄F; Li₃CoPO₄F₂;KFe(PO₃F)F; Li₂Co(PO₃F)Br₂; Li₂Fe(PO₃F₂)F; Li₂FePO₄Cl; Li₂MnPO₄OH;Li₂CoPO₄F; Li₂Fe_(0.5)Co_(0.5)PO₄F; Li₂Fe_(0.9)Mg_(0.1)PO₄F;Li₂Fe_(0.8)Mg_(0.2)PO₄F; Li_(1.25)Fe_(0.9)Mg_(0.1)PO₄F_(0.25);Li₂MnPO₄F; Li₂CoPO₄F; K₂Fe_(0.9)Mg_(0.1)P_(0.5)As_(0.5)O₄F; Li₂MnSbO₄OH;Li₂Fe_(0.6)Co_(0.4)SbO₄Br; Na₃CoAsO₄F₂; LiFe(AsO₃F)Cl;Li₂Co(As_(0.5)Sb_(0.5)O₃F)F₂; K₂Fe(AsO₃F₂)F; Li₂NiSbO₄F; Li₂FeAsO₄OH;Li₄Mn₂(PO₄)₃F; Na₄FeMn(PO₄)₃OH; Li₄FeV(PO₄)₃Br; Li₃VAl(PO₄)₃F;K₃VAl(PO₄)₃Cl; LiKNaTiFe(PO₄)₃F; Li₄Ti₂(PO₄)₃Br; Li₃V₂(PO₄)₃F₂;Li₆FeMg(PO₄)₃OH; Li₄Mn₂(AsO₄)₃F; K₄FeMn(AsO₄)₃OH;Li₄FeV(P_(0.5)Sb_(0.5)O₄)₃Br; LiNaKAlV(AsO₄)₃F; K₃VAl(SbO₄)₃Cl;Li₃TiV(SbO₄)₃F; Li₂FeMn(P_(0.5)As_(0.5)O₃F)₃; Li₄Ti₂(PO₄)₃F;Li_(3.25)V₂(PO₄)₃F_(0.25); Li₃Na_(0.75)Fe₂(PO₄)₃F_(0.75);Na_(6.5)Fe₂(PO₄)₃(OH)Cl_(0.5); K₈Ti₂(PO₄)₃F₃Br₂; K₈Ti₂(PO₄)₃F₅;Li₄Ti₂(PO₄)₃F; LiNa_(1.25)V₂(PO₄)₃F_(0.5)Cl_(0.75);K_(3.25)Mn₂(PO₄)₃OH_(0.25); LiNa_(1.25)KTiV(PO₄)₃(OH)_(1.25)Cl;Na₈Ti₂(PO₄)₃F₃Cl₂; Li₇Fe₂(PO₄)₃F₂; Li₈FeMg(PO₄)₃F_(2.25)Cl_(0.75);Li₅Na_(2.5)TiMn(PO₄)₃(OH)₂Cl_(0.5); Na₃K_(4.5)MnCa(PO₄)₃(OH)_(1.5)Br;KgFeBa(PO₄)₃F₂Cl₂; Li₇Ti₂(SiO₄)₂(PO₄)F₂; Na₈Mn₂(SiO₄)₂(PO₄)F₂Cl;Li₃K₂V₂(SiO₄)₂(PO₄)(OH)Cl; Li₄Ti₂(SiO₄)₂(PO₄)(OH);Li₂NaKV₂(SiO₄)₂(PO₄)F; Li₅TiFe(PO₄)₃F; Na₄K₂VMg(PO₄)₃FCl;Li₄NaAlNi(PO₄)₃(OH); Li₄K₃FeMg(PO₄)₃F₂; Li₂Na₂K₂CrMn(PO₄)₃(OH)Br;Li₅TiCa(PO₄)₃F; Li₄Ti_(0.75)Fe_(1.5)(PO₄)₃F; Li₃NaSnFe(PO₄)₃(OH);Li₃NaGe_(0.5)Ni₂(PO₄)₃(OH); Na₃K₂VCo(PO₄)₃(OH)Cl; Li₄Na₂MnCa(PO₄)₃F(OH);Li₃NaKTiFe(PO₄)₃F; Li₇FeCo(SiO₄)₂(PO₄)F; Li₃Na₃TiV(SiO₄)₂(PO₄)F;K_(5.5)CrMn(SiO₄)₂(PO₄)Cl_(0.5); Li₃Na_(2.5)V₂(SiO₄)₂(PO₄)(OH)_(0.5);Na_(5.25)FeMn(SiO₄)₂(PO₄)Br_(0.25); Li_(6.5)VCo(SiO₄)_(2.5)(PO₄)_(0.5)F;Na_(7.25)V₂(SiO₄)_(2.25)(PO₄)_(0.75)F₂; Li₄NaVTi(SiO₄)₃F_(0.5)Cl_(0.5);Na₂K_(2.5)ZrV(SiO₄)₃F_(0.5); Li₄K₂MnV(SiO₄)₃(OH)₂; Li₃Na₃KTi₂(SiO₄)₃F;K₆V₂(SiO₄)₃(OH)Br; Li₈FeMn(SiO₄)₃F₂; Na₃K_(4.5)MnNi(SiO₄)₃(OH)_(1.5);Li₃Na₂K₂TiV(SiO₄)₃(OH)_(0.5)Cl_(0.5); KgVCr(SiO₄)₃F₂Cl;Li₄Na₄V₂(SiO₄)₃FBr; Li₄FeMg(SO₄)₃F₂; Na₂KNiCo(SO₄)₃(OH);Na₅MnCa(SO₄)₃F₂Cl; Li₃NaCoBa(SO₄)₃FBr; Li_(2.5)K_(0.5)FeZn(SO₄)₃F;Li₃MgFe(SO₄)₃F₂; Li₂NaCaV(SO₄)₃FCl; Na₄NiMn(SO₄)₃(OH)₂; Na₂KBaFe(SO₄)₃F; Li₂KCuV(SO₄)₃(OH)Br; Li_(1.5)CoPO₄F_(0.5);Li_(1.25)CoPO₄F_(0.25); Li_(1.75)FePO₄F_(0.75); Li_(1.66)MnPO₄F_(0.66);Li_(1.5)Co_(0.75)Ca_(0.25)PO₄F_(0.5);Li_(1.75)Cu_(0.8)Mn_(0.2)PO₄F_(0.75);Li_(1.25)Fe_(0.75)Mg_(0.25)PO₄F_(0.25);Li_(1.66)Co_(0.6)Zn_(0.4)PO₄F_(0.66); KMn₂SiO₄Cl; Li₂VSiO₄(OH)₂;Li₃CoGeO₄F; LiMnSO₄F; NaFe_(0.9)Mg_(0.1)SO₄Cl; LiFeSO₄F; LiMnSO₄OH;KMnSO₄F; Li_(1.75)Mn_(0.8)Mg_(0.2)PO₄F_(0.75); Li₃FeZn(PO₄)F₂;Li_(0.5)V_(0.75)Mg_(0.5)(PO₄)F_(0.75); Li₃V_(0.5)Al_(0.5)(PO₄)F_(3.5);Li_(0.75)VCa(PO₄)F_(0.75); Li₄CuBa(PO₄)F₄;Li_(0.5)V_(0.5)Ca(PO₄)(H)_(1.5); Li_(1.5)FeMg(PO₄)(OH)Cl;LiFeCoCa(PO₄)(OH)₃F; Li₃CoBa(PO₄)(OH)₂Br₂;Li_(0.75)Mn_(1.5)Al(PO₄)(OH)_(3.75); Li₂Co_(0.75)Mg_(0.25)(PO₄)F;LiNaCu_(0.8)Mg_(0.2)(PO₄)F; NaKCo_(0.5)Mg_(0.5)(PO₄)F;LiNa_(0.5)K_(0.5)Fe_(0.75)Mg_(0.25)(PO₄)F;Li_(1.5)K_(0.5)V_(0.5)Zn_(0.5)(PO₄)F₂; Na₆Fe₂Mg(PS₄)₃(OH₂)Cl;Li₄Mn_(1.5)Co_(0.5)(PO₃F)₃(OH)_(3.5); K₈FeMg(PO₃F)₃F₃Cl₃Li₅Fe₂Mg(SO₄)₃Cl₅; LiTi₂(SO₄)₃Cl, LiMn₂(SO₄)₃F, Li₃Ni₂(SO₄)₃Cl,Li₃Co₂(SO₄)₃F, Li₃Fe₂(SO₄)₃Br, Li₃Mn₂(SO₄)₃F, Li₃MnFe(SO₄)₃F,Li₃NiCo(SO₄)₃Cl; LiMnSO₄F; LiFeSO₄Cl; LiNiSO₄F; LiCoSO₄Cl;LiMn_(1-x)Fe_(x)SO₄F, LiFe_(1-x)Mg_(x)SO₄F; Li₇ZrMn(SiO₄)₃F;Li₇MnCo(SiO₄)₃F; Li₇MnNi(SiO₄)₃F; Li₇VAl(SiO₄)₃F; Li₅MnCo(PO₄)₂(SiO₄)F;Li₄VAl(PO₄)₂(SiO₄)F; Li₄MnV(PO₄)₂(SiO₄)F; Li₄VFe(PO₄)₂(SiO₄)F;Li_(0.6)VPO₄F_(0.6); Li_(0.8)VPO₄F_(0.8); LiVP_(0.4)F; Li₃V₂(PO₄)₂F₃;LiVPO₄Cl; LiVPO₄OH; NaVPO₄F; Na₃V₂(PO₄)₂F₃; LiV_(0.9)Al_(0.1)PO₄F;LiFePO₄F; LiTiPO₄F; LiCrPO₄F; LiFePO₄; LiFe_(0.8)Mg_(0.1)PO₄;LiFe_(0.8)Mg_(0.2)PO₄; LiFe_(0.9)Ca_(0.1)PO₄; LiFe_(0.8)Ca_(0.2)PO₄;LiFe_(0.8)Zn_(0.2)PO₄; Li₃V₂(PO₄)₃; Li₃Fe₂(PO₄)₃; Li₃Mn₂(PO₄)₃;Li₃FeTi(PO₄)₃; Li₃CoMn(PO₄)₃; Li₃FeV(PO₄)₃; Li₃VTi(PO₄)₃; Li₃FeCr(PO₄)₃;Li₃FeMo(PO₄)₃; Li₃FeNi(PO₄)₃; Li₃FeMn(PO₄)₃; Li₃FeAl(PO₄)₃;Li₃FeCo(PO₄)₃; Li₃Ti₂(PO₄)₃; Li₃TiCr(PO₄)₃; Li₃TiMn(PO₄)₃;Li₃TiMo(PO₄)₃; Li₃TiCo(PO₄)₃; Li₃TiAl(PO₄)₃; Li₃TiNi(PO₄)₃;Li₃ZrMnSiP₂O₁₂; Li₃V₂SiP₂O₁₂; Li₃MnVSiP₂O₁₂; Li₃TiVSiP₂O₁₂;Li₃TiCrSiP₂O₁₂; Li_(3.5)AlVSi_(0.5)P_(2.5)O₁₂;Li_(3.5)V₂Si_(0.5)P_(2.5)O₁₂; Li_(2.5)AlCrSi_(0.5)P_(2.5)O₁₂;Li_(2.5)V₂P₃O_(11.5)F_(0.5); Li₂V₂P₃O₁₁F; Li_(2.5)VMnP₃O_(11.5)F_(0.5);Li₂V_(0.5)Fe_(1.5)P₃O₁₁F; Li₃V_(0.05)V_(0.5)P₃O_(11.5)F_(0.5);Li₃V₂P₃O₁₁F; Li₃Mn_(0.5)V_(1.5)P₃O₁₁F_(0.5);LiCo_(0.05)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Cu_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCu_(0.825)Fe_(0.1)Tio_(0.025)Mg_(0.025)PO₄;LiCu_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄;LiCu_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)Mg_(0.025)PO₄,Li_(1.025)Cu_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄,Li_(1.025)Cu_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)Mg_(0.025)PO₄,LiCu_(0.8)Fe_(0.1)Ti_(0.05)Mg_(0.05)PO₄, and mixtures thereof. Preferredactive materials include LiFePO₄; LiFe_(0.9)Mg_(0.1)PO₄;LiFe_(0.9)Mg_(0.2)PO₄;Li_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Cu_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Cu_(0.75)Fe_(0.15)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,LiCo_(0.08)Fe_(0.10)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.08)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.08)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Cu_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCo_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCo_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄; and mixtures thereof. Aparticularly preferred active material isLiCo_(0.8)Fe_(0.1)Al0.025Mg_(0.05)PO_(3.975)F_(0.025).

[0095] Methods of Manufacture:

[0096] Active materials of general formula A_(a)M_(b)(XY₄)_(c)Z_(d) arereadily synthesized by reacting starting materials in a solid statereaction, with or without simultaneous oxidation or reduction of themetal species involved. According to the desired values of a, b, c, andd in the product, starting materials are chosen that contain “a” molesof alkali metal A from all sources, “b” moles of metals M from allsources, “c” moles of phosphate (or other XY₄ species) from all sources,and “d” moles of halide or hydroxide Z, again taking into account allsources. As discussed below, a particular starting material may be thesource of more than one of the components A, M, XY₄, or Z. Alternativelyit is possible to run the reaction with an excess of one or more of thestarting materials. In such a case, the stoichiometry of the productwill be determined by the limiting reagent among the components A, M,XY₄, and Z. Because in such a case at least some of the startingmaterials will be present in the reaction product mixture, it is usuallydesirable to provide exact molar amounts of all the starting materials.

[0097] In one aspect, the moiety XY₄ of the active material comprises asubstituted group represented by X′O_(4-x)Y′_(x) where x is less than orequal to 1, and preferably less than or equal to about 0.1. Such groupsmay be synthesized by providing starting materials containing, inaddition to the alkali metal and other metals, phosphate or other X′O₄material in a molar amount equivalent to the amount necessary to producea reaction product containing X′O₄. Where Y′ is F, the startingmaterials further comprise a source of fluoride in a molar amountsufficient to substitute F in the product as shown in the formula. Thisis generally accomplished by including at least “x” moles of F in thestarting materials. For embodiments where d>0, the fluoride source isused in a molar limiting quantity such that the fluorine is incorporatedas a Z-moiety. Sources of F include ionic compounds containing fluorideion (F⁻) or hydrogen difluoride ion (HF₂ ⁻). The cation may be anycation that forms a stable compound with the fluoride or hydrogendifluoride anion. Examples include +1, +2, and +3 metal cations, as wellas ammonium and other nitrogen-containing cations. Ammonium is apreferred cation because it tends to form volatile by-products that arereadily removed from the reaction mixture.

[0098] Similarly, to make X′O_(4-x)N_(x), starting materials areprovided that contain “x” moles of a source of nitride ion. Sources ofnitride are among those known in the art including nitride salts such asLi₃N and (NH₄)₃N.

[0099] It is preferred to synthesize the active materials of theinvention using stoichiometric amounts of the starting materials, basedon the desired composition of the reaction product expressed by thesubscripts a, b, c, and d above. Alternatively it is possible to run thereaction with a stoichiometric excess of one or more of the startingmaterials. In such a case, the stoichiometry of the product will bedetermined by the limiting reagent among the components. There will alsobe at least some unreacted starting material in the reaction productmixture. Because such impurities in the active materials are generallyundesirable (with the exception of reducing carbon, discussed below), itis generally preferred to provide relatively exact molar amounts of allthe starting materials.

[0100] The sources of components A, M, phosphate (or other XY₄ moiety)and optional sources of F or N discussed above, and optional sources ofZ may be reacted together in the solid state while heating for a timeand at a temperature sufficient to make a reaction product. The startingmaterials are provided in powder or particulate form. The powders aremixed together with any of a variety of procedures, such as by ballmilling, blending in a mortar and pestle, and the like. Thereafter themixture of powdered starting materials may be compressed into a pelletand/or held together with a binder material to form a closely coheringreaction mixture. The reaction mixture is heated in an oven, generallyat a temperature of about 400° C. or greater until a reaction productforms.

[0101] Another means for carrying out the reaction at a lowertemperature is a hydothermal method. In a hydrothermal reaction, thestarting materials are mixed with a small amount of a liquid such aswater, and placed in a pressurized bomb. The reaction temperature islimited to that which can be achieved by heating the liquid water underpressure, and the particular reaction vessel used.

[0102] The reaction may be carried out without redox, or if desired,under reducing or oxidizing conditions. When the reaction is carried outunder reducing conditions, at least some of the transition metals in thestarting materials are reduced in oxidation state. When the reaction isdone without redox, the oxidation state of the metal or mixed metals inthe reaction product is the same as in the starting materials. Oxidizingconditions may be provided by running the reaction in air. Thus, oxygenfrom the air is used to oxidize the starting material containing thetransition metal.

[0103] The reaction may also be carried out with reduction. For example,the reaction may be carried out in a reducing atmosphere such ashydrogen, ammonia, methane, or a mixture of reducing gases.Alternatively, the reduction may be carried out in situ by including inthe reaction mixture a reductant that will participate in the reactionto reduce a metal M, but that will produce by-products that will notinterfere with the active material when used later in an electrode or anelectrochemical cell. The reductant is described in greater detailbelow.

[0104] Sources of alkali metal include any of a number of salts or ioniccompounds of lithium, sodium, potassium, rubidium or cesium. Lithium,sodium, and potassium compounds are preferred, with lithium beingparticularly preferred. Preferably, the alkali metal source is providedin powder or particulate form. A wide range of such materials is wellknown in the field of inorganic chemistry. Examples include the lithium,sodium, and/or potassium fluorides, chlorides, bromides, iodides,nitrates, nitrites, sulfates, hydrogen sulfates, sulfites, bisulfites,carbonates, bicarbonates, borates, phosphates, hydrogen ammoniumphosphates, dihydrogen ammonium phosphates, silicates, antimonates,arsenates, germinates, oxides, acetates, oxalates, and the like.Hydrates of the above compounds may also be used, as well as mixtures.In particular, the mixtures may contain more than one alkali metal sothat a mixed alkali metal active material will be produced in thereaction.

[0105] Sources of metals M, M¹, M², M³, and M⁴ include salts orcompounds of any of the transition metals, alkaline earth metals, orlanthamide metals, as well as of non-transition elements such as boron,aluminum, gallium, indium, thallium, germanium, tin, lead, antimony, andbismuth. The metal salts or compounds include fluorides, chlorides,bromides, iodides, nitrates, nitrites, sulfates, hydrogen sulfates,sulfites, bisulfites, carbonates, bicarbonates, borates, phosphates,hydrogen ammonium phosphates, dihydrogen ammonium phosphates, silicates,antimonates, arsenates, germanates, oxides, hydroxides, acetates,oxalates, and the like. Hydrates may also be used. The metal M in thestarting material may have any oxidation state, depending on theoxidation state required in the desired product and the oxidizing orreducing conditions contemplated, as discussed below. In particular, thecobalt and iron of the active materials may be provided by startingmaterials with Co⁺², Co⁺³, Fe⁺², or Fe⁺³. The metal sources are chosenso that at least one metal in the final reaction product is capable ofbeing in an oxidation state higher than it is in the reaction product.In a preferred embodiment, the metal sources also include a +2non-transition metal. Also preferably, at least one metal source is asource of a +3 non-transition metal. In embodiments comprising Ti, asource of Ti is provided in the starting materials and the compounds aremade using reducing or non-reducing conditions depending on the othercomponents of the product and the desired oxidation state of Ti andother metals in the final product. Suitable Ti-containing precursorsinclude TiO₂, Ti₂O₃, and TiO.

[0106] Sources of the desired starting material anions, such asphosphates, halides and hydroxides, are provided by a number of salts orcompounds containing positively charged cations in addition to a sourceof phosphate (or other XY₄ species), halide, or hydroxide. Such cationsinclude metal ions such as the alkali metals, alkaline metals,transition metals, or other non-transition elements, as well as complexcations such as ammonium or quaternary ammonium. The phosphate anion insuch compounds may be phosphate, hydrogen ammonium phosphate, ordihydrogen ammonium phosphate. As with the alkali metal source and metalsource discussed above, the phosphate or other XY₄ species, halide andhydroxide starting materials are preferably provided in particulate orpowder form. Hydrates of any of the above may be used, as can mixturesof the above.

[0107] As noted above, the active materials A_(a)M_(b)(XY₄)_(c)Z_(d) ofthe invention can contain a mixture of alkali metals A, a mixture ofmetals M, a phosphate group representative of the XY₄ group in theformula and, optionally, a halide or hydroxide Z. In another aspect ofthe invention, the phosphate group can be completely or partiallysubstituted by a number of other XY₄ moieties, which will also bereferred to as “phosphate replacements” or “modified phosphates.” Thus,active materials are provided according to the invention wherein the XY₄moiety is a phosphate group that is completely or partially replaced bysuch moieties as sulfate (SO₄)²⁻, monofluoromonophosphate, (PO₃F)²⁻,difluoromonophosphate (PO₂F)²⁻, silicate (SiO₄)⁴⁻, arsenate, antimonate,and germanate. Analogues of the above oxygenate anions where some or allof the oxygen is replaced by sulfur are also useful in the activematerials of the invention, with the exception that the sulfate groupmay not be completely substituted with sulfur. For examplethiomonophosphates may also be used as a complete or partial replacementfor phosphate in the active materials of the invention. Suchthiomonophosphates include the anions (PO₃S)³⁻, (PO₂S₂)³⁻, (POS₃)³⁻, and(PS₄)³⁻. They are most conveniently available as the sodium, lithium, orpotassium derivative.

[0108] To synthesize the active materials containing the modifiedphosphate moieties, it is usually possible to substitute all orpreferably only part of the phosphate compounds discussed above with asource of the replacement anion. The replacement is considered on astoichiometric basis. Starting materials providing the source of thereplacement anions are provided along with the other starting materialsas discussed above. Synthesis of the active materials containing themodified phosphate groups proceeds as discussed above, either withoutredox or under oxidizing or reducing conditions. As was the case withthe phosphate compounds, the compound containing the modified orreplacement phosphate group or groups may also be a source of othercomponents of the active materials. For example, the alkali metal and/orany of the other metals may be a part of the modified phosphatecompound.

[0109] Non-limiting examples of sources of monofluoromonophosphatesinclude Na₂PO₃F, K₂PO₃F, (NH₄)₂PO₃F.H₂O, LiNaPO₃F.H₂O, LiKPO₃F,LiNH₄PO₃F, NaNH₄PO₃F, NaK₃(PO₃F)₂ and CaPO₃F.2H₂O. Representativeexamples of sources of difluoromonophosphate compounds include, withoutlimitation, NH₄PO₂F₂, NaPO₂F₂, KPO₂F₂, Al(PO₂F₂)₃, and Fe(PO₂F₂)₃.

[0110] When it is desired to partially or completely replace phosphorousin the active materials with silicon, it is possible to use a widevariety of silicates and other silicon containing compounds. Thus,useful sources of silicon in the active materials of the inventioninclude orthosilicates, pyrosilicates, cyclic silicate anions such as(Si₃O₉)⁶⁻, (Si₆O₁₈)¹²⁻ and the like, and pyrocenes represented by theformula [(SiO₃)²⁻]_(n), for example LiAl(SiO₃)₂. Silica or SiO₂ may alsobe used. Partial substitution of silicate for phosphate is illustratedin Example 4.

[0111] Representative arsenate compounds that may be used to prepare theactive materials of the invention include H₃AsO₄ and salts of the anions[H₂AsO₄]⁻ and [HAsO₄]²⁻. Sources of antimonate in the active materialscan be provided by antimony-containing materials such as Sb₂O₅,M^(I)SbO₃ where M^(I) is a metal having oxidation state +1, M^(III)SbO₄where M^(III) is a metal having an oxidation state of +3, andM^(II)Sb₂O₇ where M^(II) is a metal having an oxidation state of +2.Additional sources of antimonate include compounds such as Li₃SbO₄,NH₄H₂SbO₄, and other alkali metal and/or ammonium mixed salts of the[SbO₄]³⁻ anion.

[0112] Sources of sulfate compounds that can be used to partially orcompletely replace phosphorous in the active materials with sulfurinclude alkali metal and transition metal sulfates and bisulfates aswell as mixed metal sulfates such as (NH₄)₂Fe(SO₄)₂, NH₄Fe(SO₄)₂ and thelike. Finally, when it is desired to replace part or all of thephosphorous in the active materials with germanium, a germaniumcontaining compound such as GeO₂ may be used.

[0113] To prepare the active materials containing the modified phosphategroups, it generally suffices to choose the stoichiometry of thestarting materials based on the desired stoichiometry of the modifiedphosphate groups in the final product and react the starting materialstogether according to the procedures described above with respect to thephosphate materials. Naturally, partial or complete substitution of thephosphate group with any of the above modified or replacement phosphategroups will entail a recalculation of the stoichiometry of the requiredstarting materials.

[0114] A starting material may provide more than one of the componentsA, M, XY₄, and Z, as is evident in the list above. In variousembodiments of the invention, starting materials are provided thatcombine, for example, the metal and the phosphate, thus requiring onlythe alkali metal to be added. In one embodiment, a starting material isprovided that contains alkali metal, metal, and phosphate. As a generalrule, there is flexibility to select starting materials containing anyof the components of alkali metal A, metal M, and phosphate (or otherXY₄ moiety), as well as halide or hydroxide Z, depending onavailability. Combinations of starting materials providing each of thecomponents may also be used.

[0115] In general, any anion may be combined with the alkali metalcation to provide the alkali metal source starting material, or with ametal M cation to provide a metal starting material. Likewise, anycation may be combined with the halide or hydroxide anion to provide thesource of Z component starting material, and any cation may be used ascounterion to the phosphate or similar XY₄ component. It is preferred,however, to select starting materials with counterions that give rise tothe formation of volatile by-products during the solid state reaction.Thus, it is desirable to choose ammonium salts, carbonates,bicarbonates, oxides, hydroxides, and the like where possible. Startingmaterials with these counterions tend to form volatile by-products suchas water, ammonia, and carbon dioxide, which can be readily removed fromthe reaction mixture. Similarly, sulfur-containing anions such assulfate, bisulfate, sulfite, bisulfite and the like tend to result involatile sulfur oxide by-products. Nitrogen-containing anions such asnitrate and nitrite also tend to give volatile NO_(x) by-products.

[0116] As noted above, the reactions may be carried out withoutreduction, or in the presence of a reductant. In one aspect, thereductant, which provides reducing power for the reactions, may beprovided in the form of a reducing carbon by including a source ofelemental carbon along with the other particulate starting materials. Inthis case, the reducing power is provided by simultaneous oxidation ofcarbon to either carbon monoxide or carbon dioxide.

[0117] The starting materials containing transition metal compounds aremixed together with carbon, which is included in an amount sufficient toreduce the metal ion of one or more of the metal-containing startingmaterials without full reduction to an elemental metal state. (Excessquantities of the reducing carbon may be used to enhance productquality.) An excess of carbon, remaining after the reaction, functionsas a conductive constituent in the ultimate electrode formulation. Thisis an advantage since such remaining carbon is very intimately mixedwith the product active material. Accordingly, large quantities ofexcess carbon, on the order of 100% excess carbon or greater are useablein the process. In a preferred embodiment, the carbon present duringcompound formation is intimately dispersed throughout the precursor andproduct. This provides many advantages, including the enhancedconductivity of the product. In a preferred embodiment, the presence ofcarbon particles in the starting materials also provides nucleationsites for the production of the product crystals.

[0118] Alternatively or in addition, the source of reducing carbon maybe provided by an organic material. The organic material ischaracterized as containing carbon and at least one other element,preferably hydrogen. The organic material generally forms adecomposition product, referred to herein as a carbonaceous material,upon heating under the conditions of the reaction. Without being boundby theory, representative decomposition processes that can lead to theformation of the carbonaceous material include pyrolization,carbonization, coking, destructive distillation, and the like. Theseprocess names, as well as the term thermal decomposition, are usedinterchangeably in this application to refer to the process by which adecomposition product capable of acting as a reductant is formed uponheating of a reaction mixture containing an organic material.

[0119] A typical decomposition product contains carbonaceous material.During reaction in a preferred embodiment, at least a portion of thecarbonaceous material formed participates as a reductant. That portionthat participates as reductant may form a volatile by-product such asdiscussed below. Any volatile by-product formed tends to escape from thereaction mixture so that it is not incorporated into the reactionproduct.

[0120] Although the invention is understood not to be limited as to themechanism of action of the organic precursor material, it believed thatthe carbonaceous material formed from decomposition of the organicmaterial provides reducing power similar to that provided by elementalcarbon discussed above. For example, the carbonaceous material mayproduce carbon monoxide or carbon dioxide, depending on the temperatureof the reaction.

[0121] In a preferred embodiment, some of the organic material providingreducing power is oxidized to a non-volatile component, such as forexample, oxygen-containing carbon materials such as alcohols, ketones,aldehydes, esters, and carboxylic acids and anhydrides. Suchnon-volatile by-products, as well as any carbonaceous material that doesnot participate as reductant (for example, any present in stoichiometricexcess or any that does not otherwise react) will tend to remain in thereaction mixture along with the other reaction products, but will not besignificantly covalently incorporated.

[0122] The carbonaceous material prepared by heating the organicprecursor material will preferably be enriched in carbon relative to themole percent carbon present in the organic material. The carbonaceousmaterial preferably contains from about 50 up to about 100 mole percentcarbon.

[0123] While in some embodiments the organic precursor material forms acarbonaceous decomposition product that acts as a reductant as discussedabove with respect to elemental carbon, in other embodiments a portionof the organic material may participate as reductant without firstundergoing a decomposition. The invention is not limited by the exactmechanism or mechanisms of the underlying reduction processes.

[0124] As with elemental carbon, reactions with the organic precursormaterial are conveniently carried out by combining starting materialsand heating. The starting materials include at least one transitionmetal compound as noted above. For convenience, it is preferred to carryout the decomposition of the organic material and the reduction of atransition metal in one step. In this embodiment, the organic materialdecomposes in the presence of the transition metal compound to form adecomposition product capable of acting as a reductant, which reactswith the transition metal compound to form a reduced transition metalcompound. In another embodiment, the organic material may be decomposedin a separate step to form a decomposition product. The decompositionproduct may then be combined with a transition metal compound to form amixture. The mixture may then be heated for a time and at a temperaturesufficient to form a reaction product comprising a reduced transitionmetal compound.

[0125] The organic precursor material may be any organic materialcapable of undergoing pyrolysis or carbonization, or any otherdecomposition process that leads to a carbonaceous material rich incarbon. Such precursors include in general any organic material, i.e.,compounds characterized by containing carbon and at least one otherelement. Although the organic material may be a perhalo compoundcontaining essentially no carbon-hydrogen bonds, typically the organicmaterials contain carbon and hydrogen. Other elements, such as halogens,oxygen, nitrogen, phosphorus, and sulfur, may be present in the organicmaterial, as long as they do not significantly interfere with thedecomposition process or otherwise prevent the reductions from beingcarried out. Precursors include organic hydrocarbons, alcohols, esters,ketones, aldehydes, carboxylic acids, sulfonates, and ethers. Preferredprecursors include the above species containing aromatic rings,especially the aromatic hydrocarbons such as tars, pitches, and otherpetroleum products or fractions. As used here, hydrocarbon refers to anorganic compound made up of carbon and hydrogen, and containing nosignificant amounts of other elements. Hydrocarbons may containimpurities having some heteroatoms. Such impurities might result, forexample, from partial oxidation of a hydrocarbon or incompleteseparation of a hydrocarbon from a reaction mixture or natural sourcesuch as petroleum.

[0126] Other organic precursor materials include sugars and othercarbohydrates, including derivatives and polymers. Examples of polymersinclude starch, cellulose, and their ether or ester derivatives. Otherderivatives include the partially reduced and partially oxidizedcarbohydrates discussed below. On heating, carbohydrates readilydecompose to form carbon and water. The term carbohydrates as used hereencompasses the D-, L-, and DL-forms, as well as mixtures, and includesmaterial from natural or synthetic sources.

[0127] In one sense as used in the invention, carbohydrates are organicmaterials that can be written with molecular formula (C)_(m) (H²⁰)_(n),where m and n are integers. For simple hexose or pentose sugars, m and nare equal to each other. Examples of hexoses of formula C₆H₁₂O₆ includeallose, altose, glucose, mannose, gulose, inose, galactose, talose,sorbose, tagatose, and fructose. Pentoses of formula C₅H₁₀O₅ includeribose, arabinose, and xylose. Tetroses include erythrose and threose,while glyceric aldehyde is a triose. Other carbohydrates include thetwo-ring sugars (di-saccharides) of general formula C₁₂H₂₂O₁₁. Examplesinclude sucrose, maltose, lactose, trehalose, gentiobiose, cellobiose,and melibiose. Three-ring (trisaccharides such as raffinose) and higheroligomeric and polymer carbohydrates may also be used. Examples includestarch and cellulose. As noted above, the carbohydrates readilydecompose to carbon and water when heated to a sufficiently hightemperature. The water of decomposition tends to turn to steam under thereaction conditions and volatilize.

[0128] It will be appreciated that other materials will also tend toreadily decompose to H₂O and a material very rich in carbon. Suchmaterials are also intended to be included in the term “carbohydrate” asused in the invention. Such materials include slightly reducedcarbohydrates such as glycerol, sorbitol, mannitol, iditol, dulcitol,talitol, arabitol, xylitol, and adonitol, as well as “slightly oxidized”carbohydrates such as gluconic, mannonic, glucuronic, galacturonic,mannuronic, saccharic, manosaccharic, ido-saccharic, mucic, talo-mucic,and allo-mucic acids. The formula of the slightly oxidized and theslightly reduced carbohydrates is similar to that of the carbohydrates.

[0129] A preferred carbohydrate is sucrose. Under the reactionconditions, sucrose melts at about 150-180° C. Preferably, the liquidmelt tends to distribute itself among the starting materials. Attemperatures above about 450° C., sucrose and other carbohydratesdecompose to form carbon and water. The as-decomposed carbon powder isin the form of fresh amorphous fine particles with high surface area andhigh reactivity.

[0130] The organic precursor material may also be an organic polymer.Organic polymers include polyolefins such as polyethylene andpolypropylene, butadiene polymers, isoprene polymers, vinyl alcoholpolymers, furfuryl alcohol polymers, styrene polymers includingpolystyrene, polystyrene-polybutadiene and the like, divinylbenzenepolymers, naphthalene polymers, phenol condensation products includingthose obtained by reaction with aldehyde, polyacrylonitrile, polyvinylacetate, as well as cellulose starch and esters and ethers thereofdescribed above.

[0131] In some embodiments, the organic precursor material is a solidavailable in particulate form. Particulate materials may be combinedwith the other particulate starting materials and reacted by heatingaccording to the methods described above.

[0132] In other embodiments, the organic precursor material may be aliquid. In such cases, the liquid precursor material is combined withthe other particulate starting materials to form a mixture. The mixtureis heated, whereupon the organic material forms a carbonaceous materialin situ. The reaction proceeds with carbothermal reduction. The liquidprecursor materials may also advantageously serve or function as abinder in the starting material mixture as noted above.

[0133] Reducing carbon is preferably used in the reactions instoichiometric excess. To calculate relative molar amounts of reducingcarbon, it is convenient to use an “equivalent” weight of the reducingcarbon, defined as the weight per gram-mole of carbon atom. Forelemental carbons such as carbon black, graphite, and the like, theequivalent weight is about 12 g/equivalent. For other organic materials,the equivalent weight per gram-mole of carbon atoms is higher. Forexample, hydrocarbons have an equivalent weight of about 14g/equivalent. Examples of hydrocarbons include aliphatic, alicyclic, andaromatic hydrocarbons, as well as polymers containing predominantly orentirely carbon and hydrogen in the polymer chain. Such polymers includepolyolefins and aromatic polymers and copolymers, includingpolyethylenes, polypropylenes, polystyrenes, polybutadienes, and thelike. Depending on the degree of unsaturation, the equivalent weight maybe slightly above or below 14.

[0134] For organic materials having elements other than carbon andhydrogen, the equivalent weight for the purpose of calculating astoichiometric quantity to be used in the reactions is generally higherthan 14. For example, in carbohydrates it is about 30 g/equivalent.Examples of carbohydrates include sugars such as glucose, fructose, andsucrose, as well as polymers such as cellulose and starch.

[0135] Although the reactions may be carried out in oxygen or air, theheating is preferably conducted under an essentially non-oxidizingatmosphere. The atmosphere is essentially non-oxidizing so as not tointerfere with the reduction reactions taking place. An essentiallynon-oxidizing atmosphere can be achieved through the use of vacuum, orthrough the use of inert gases such as argon, nitrogen, and the like.Although oxidizing gas (such as oxygen or air), may be present, itshould not be at so great a concentration that it interferes with thecarbothermal reduction or lowers the quality of the reaction product. Itis believed that any oxidizing gas present will tend to react with thereducing carbon and lower the availability of the carbon forparticipation in the reaction. To some extent, such a contingency can beanticipated and accommodated by providing an appropriate excess ofreducing carbon as a starting material. Nevertheless, it is generallypreferred to carry out the carbothermal reduction in an atmospherecontaining as little oxidizing gas as practical.

[0136] In a preferred embodiment, reduction is carried out in a reducingatmosphere in the presence of a reductant as discussed above. The term“reducing atmosphere” as used herein means a gas or mixture of gasesthat is capable of providing reducing power for a reaction that iscarried out in the atmosphere. Reducing atmospheres preferably containone or more so-called reducing gases. Examples of reducing gases includehydrogen, carbon monoxide, methane, and ammonia, as well as mixturesthereof. Reducing atmospheres also preferably have little or nooxidizing gases such as air or oxygen. If any oxidizing gas is presentin the reducing atmosphere, it is preferably present at a level lowenough that it does not significantly interfere with any reductionprocesses taking place.

[0137] The stoichiometry of the reduction can be selected along with therelative stoichiometric amounts of the starting components A, M, PO₄ (orother XY₄ moiety), and Z. It is usually easier to provide the reducingagent in stoichiometric excess and remove the excess, if desired, afterthe reaction. In the case of the reducing gases and the use of reducingcarbon such as elemental carbon or an organic material, any excessreducing agent does not present a problem. In the former case, the gasis volatile and is easily separated from the reaction mixture, while inthe latter, the excess carbon in the reaction product does not harm theproperties of the active material, particularly in embodiments wherecarbon is added to the active material to form an electrode material foruse in the electrochemical cells and batteries of the invention.Conveniently also, the by-products carbon monoxide or carbon dioxide (inthe case of carbon) or water (in the case of hydrogen) are readilyremoved from the reaction mixture.

[0138] When using a reducing atmosphere, it is difficult to provide lessthan an excess of reducing gas such as hydrogen. Under such as asituation, it is preferred to control the stoichiometry of the reactionby the other limiting reagents. Alternatively the reduction may becarried out in the presence of reducing carbon such as elemental carbon.Experimentally, it would be possible to use precise amounts of reductantcarbon to make products of a chosen stoichiometry. However, it ispreferred to carry out the carbothermal reduction in a molar excess ofcarbon. As with the reducing atmosphere, this is easier to doexperimentally, and it leads to a product with excess carbon dispersedinto the reaction product, which as noted above provides a useful activeelectrode material.

[0139] Before reacting the mixture of starting materials, the particlesof the starting materials are intermingled. Preferably, the startingmaterials are in particulate form, and the intermingling results in anessentially homogeneous powder mixture of the precursors. In oneembodiment, the precursor powders are dry-mixed using, for example, aball mill. Then the mixed powders are pressed into pellets. In anotherembodiment, the precursor powders are mixed with a binder. The binder ispreferably selected so as not to inhibit reaction between particles ofthe powders. Preferred binders decompose or evaporate at a temperatureless than the reaction temperature. Examples include mineral oils,glycerol, and polymers that decompose or carbonize to form a carbonresidue before the reaction starts, or that evaporate before thereaction starts. In one embodiment, the binders used to hold the solidparticles also function as sources of reducing carbon, as describedabove. In still another embodiment, intermingling is accomplished byforming a wet mixture using a volatile solvent and then the intermingledparticles are pressed together in pellet form to provide goodgrain-to-grain contact.

[0140] The mixture of starting materials is heated for a time and at atemperature sufficient to form an inorganic transition metal compoundreaction product. If the starting materials include a reducing agent,the reaction product is a transition metal compound having at least onetransition metal in a lower oxidation state relative to its oxidationstate in the starting materials.

[0141] Preferably, the particulate starting materials are heated to atemperature below the melting point of the starting materials.Preferably, at least a portion of the starting material remains in thesolid state during the reaction.

[0142] The temperature should preferably be about 400° C. or greater,and desirably about 450° C. or greater, and preferably about 500° C. orgreater, and generally will proceed at a faster rate at highertemperatures. The various reactions involve production of CO or CO₂ asan effluent gas. The equilibrium at higher temperature favors COformation. Some of the reactions are more desirably conducted attemperatures greater than about 600° C.; most desirably greater thanabout 650° C.; preferably about 700° C. or greater; more preferablyabout 750° C. or greater. Suitable ranges for many reactions are fromabout 700 to about 950° C., or from about 700 to about 800° C.

[0143] Generally, the higher temperature reactions produce CO effluentand the stoichiometry requires more carbon be used than the case whereCO₂ effluent is produced at lower temperature. This is because thereducing effect of the C to CO₂ reaction is greater than the C to COreaction. The C to CO₂ reaction involves an increase in carbon oxidationstate of +4 (from 0 to 4) and the C to CO reaction involves an increasein carbon oxidation state of +2 (from ground state zero to 2). Here,higher temperature generally refers to a range of about 650° C. to about1000° C. and lower temperature refers to up to about 650° C.Temperatures higher than about 1200° C. are not thought to be needed.

[0144] In one embodiment, the methods of this invention utilize thereducing capabilities of carbon in a unique and controlled manner toproduce desired products having structure and alkali metal contentsuitable for use as electrode active materials. The advantages are atleast in part achieved by the reductant, carbon, having an oxide whosefree energy of formation becomes more negative as temperature increases.Such oxide of carbon is more stable at high temperature than at lowtemperature. This feature is used to produce products having one or moremetal ions in a reduced oxidation state relative to the precursor metalion oxidation state.

[0145] Referring back to the discussion of temperature, at about 700° C.both the carbon to carbon monoxide and the carbon to carbon dioxidereactions are occurring. At closer to about 600° C. the C to CO₂reaction is the dominant reaction. At closer to about 800° C. the C toCO reaction is dominant. Since the reducing effect of the C to CO₂reaction is greater, the result is that less carbon is needed per atomicunit of metal to be reduced. In the case of carbon to carbon monoxide,each atomic unit of carbon is oxidized from ground state zero to plus 2.Thus, for each atomic unit of metal ion (M) which is being reduced byone oxidation state, one half atomic unit of carbon is required. In thecase of the carbon to carbon dioxide reaction, one quarter atomic unitof carbon is stoichiometrically required for each atomic unit of metalion (M) which is reduced by one oxidation state, because carbon goesfrom ground state zero to a plus 4 oxidation state. These samerelationships apply for each such metal ion being reduced and for eachunit reduction in oxidation state desired.

[0146] The starting materials may be heated at ramp rates from afraction of a degree up to about 10° C. per minute. Higher or lower ramprates may be chosen depending on the available equipment, desiredturnaround, and other factors. It is also possible to place the startingmaterials directly into a pre-heated oven. Once the desired reactiontemperature is attained, the reactants (starting materials) are held atthe reaction temperature for a time sufficient for reaction to occur.Typically the reaction is carried out for several hours at the finalreaction temperature. The heating is preferably conducted undernon-oxidizing or inert gas such as argon or vacuum, or in the presenceof a reducing atmosphere.

[0147] After reaction, the products are preferably cooled from theelevated temperature to ambient (room) temperature (i.e., about 10° C.to about 40° C.). The rate of cooling may vary according to a number offactors including those discussed above for heating rates. For example,the cooling may be conducted at a rate similar to the earlier ramp rate.Such a cooling rate has been found to be adequate to achieve the desiredstructure of the final product. It is also possible to quench theproducts to achieve a higher cooling rate, for example on the order ofabout 100° C./minute.

[0148] The general aspects of the above synthesis routes are applicableto a variety of starting materials. The metal compounds may be reducedin the presence of a reducing agent, such as hydrogen or carbon. Thesame considerations apply to other metal and phosphate containingstarting materials. The thermodynamic considerations such as ease ofreduction of the selected starting materials, the reaction kinetics, andthe melting point of the salts will cause adjustment in the generalprocedure, such as the amount of reducing agent, the temperature of thereaction, and the dwell time.

[0149] Electrodes:

[0150] The present invention also provides electrodes comprising anelectrode active material of the present invention. In a preferredembodiment, the electrodes of the present invention comprise anelectrode active material of this invention, a binder; and anelectrically conductive carbonaceous material.

[0151] In a preferred embodiment, the electrodes of this inventioncomprise:

[0152] (a) from about 25% to about 95%, more preferably from about 50%to about 90%, active material;

[0153] (b) from about 2% to about 95% electrically conductive material(e.g., carbon black); and

[0154] (c) from about 3% to about 20% binder chosen to hold allparticulate materials in contact with one another without degradingionic conductivity.

[0155] (Unless stated otherwise, all percentages herein are by weight.)Cathodes of this invention preferably comprise from about 50% to about90% of active material, about 5% to about 30% of the electricallyconductive material, and the balance comprising binder. Anodes of thisinvention preferably comprise from about 50% to about 95% by weight ofthe electrically conductive material (e.g., a preferred graphite), withthe balance comprising binder.

[0156] Electrically conductive materials among those useful hereininclude carbon black, graphite, powdered nickel, metal particles,conductive polymers (e.g., characterized by a conjugated network ofdouble bonds like polypyrrole and polyacetylene), and mixtures thereof.Binders useful herein preferably comprise a polymeric material andextractable plasticizer suitable for forming a bound porous composite.Preferred binders include halogenated hydrocarbon polymers (such aspoly(vinylidene chloride) and poly((dichloro-1,4-phenylene)ethylene),fluorinated urethanes, fluorinated epoxides, fluorinated acrylics,copolymers of halogenated hydrocarbon polymers, epoxides, ethylenepropylene diamine termonomer (EPDM), ethylene propylene diaminetermonomer (EPDM), polyvinylidene difluoride (PVDF), hexafluoropropylene(HFP), ethylene acrylic acid copolymer (EAA), ethylene vinyl acetatecopolymer (EVA), EAA/EVA copolymers, PVDF/HFP copolymers, and mixturesthereof.

[0157] In a preferred process for making an electrode, the electrodeactive material is mixed into a slurry with a polymeric binder compound,a solvent, a plasticizer, and optionally the electroconductive material.The active material slurry is appropriately agitated, and then thinlyapplied to a substrate via a doctor blade. The substrate can be aremovable substrate or a functional substrate, such as a currentcollector (for example, a metallic grid or mesh layer) attached to oneside of the electrode film. In one embodiment, heat or radiation isapplied to evaporate the solvent from the electrode film, leaving asolid residue. The electrode film is further consolidated, where heatand pressure are applied to the film to sinter and calendar it. Inanother embodiment, the film may be air-dried at moderate temperature toyield self-supporting films of copolymer composition. If the substrateis of a removable type it is removed from the electrode film, andfurther laminated to a current collector. With either type of substrateit may be necessary to extract the remaining plasticizer prior toincorporation into the battery cell.

[0158] Batteries:

[0159] The batteries of the present invention comprise:

[0160] (a) a first electrode comprising an active material of thepresent invention;

[0161] (b) a second electrode which is a counter-electrode to said firstelectrode; and

[0162] (c) an electrolyte between said electrodes.

[0163] The electrode active material of this invention may comprise theanode, the cathode, or both. Preferably, the electrode active materialcomprises the cathode.

[0164] The active material of the second, counter-electrode is anymaterial compatible with the electrode active material of thisinvention. In embodiments where the electrode active material comprisesthe cathode, the anode may comprise any of a variety of compatibleanodic materials well known in the art, including lithium, lithiumalloys, such as alloys of lithium with aluminum, mercury, manganese,iron, zinc, and intercalation based anodes such as those employingcarbon, tungsten oxides, and mixtures thereof. In a preferredembodiment, the anode comprises:

[0165] (a) from about 0% to about 95%, preferably from about 25% toabout 95%, more preferably from about 50% to about 90%, of an insertionmaterial;

[0166] (b) from about 2% to about 95% electrically conductive material(e.g., carbon black); and

[0167] (c) from about 3% to about 20% binder chosen to hold allparticulate materials in contact with one another without degradingionic conductivity.

[0168] In a particularly preferred embodiment, the anode comprises fromabout 50% to about 90% of an insertion material selected from the groupactive material from the group consisting of metal oxides (particularlytransition metal oxides), metal chalcogenides, and mixtures thereof. Inanother preferred embodiment, the anode does not contain an insertionactive, but the electrically conductive material comprises an insertionmatrix comprising carbon, graphite, cokes, mesocarbons and mixturesthereof. One preferred anode intercalation material is carbon, such ascoke or graphite, which is capable of forming the compound LixC.Insertion anodes among those useful herein are described in U.S. Pat.No. 5,700,298, Shi et al., issued Dec. 23, 1997; U.S. Pat. No.5,712,059, Barker et al., issued Jan. 27, 1998; U.S. Pat. No. 5,830,602,Barker et al., issued Nov. 3, 1998; and U.S. Pat. No. 6,103,419, Saidiet al., issued Aug. 15, 2000; all of which are incorporated by referenceherein.

[0169] In embodiments where the electrode active material comprises theanode, the cathode preferably comprises:

[0170] (a) from about 25% to about 95%, more preferably from about 50%to about 90%, active material;

[0171] (b) from about 2% to about 95% electrically conductive material(e.g., carbon black); and

[0172] (c) from about 3% to about 20% binder chosen to hold allparticulate materials in contact with one another without degradingionic conductivity.

[0173] Active materials useful in such cathodes include electrode activematerials of this invention, as well as metal oxides (particularlytransition metal oxides), metal chalcogenides, and mixtures thereof.Other active materials include lithiated transition metal oxides such asLiCoO₂, LiNiO₂, and mixed transition metal oxides such asLiCo_(1-m)Ni_(m)O₂, where 0<m<1. Another preferred active materialincludes lithiated spinel active materials exemplified by compositionshaving a structure of LiMn₂O₄, as well as surface treated spinels suchas disclosed in U.S. Pat. No. 6,183,718, Barker et al., issued Feb. 6,2001, incorporated by reference herein. Blends of two or more of any ofthe above active materials may also be used. The cathode mayalternatively further comprise a basic compound to protect againstelectrode degradation as described in U.S. Pat. No. 5,869,207, issuedFeb. 9, 1999, incorporated by reference herein.

[0174] The batteries of this invention also comprise a suitableelectrolyte that provides a physical separation but allows transfer ofions between the cathode and anode. The electrolyte is preferably amaterial that exhibits high ionic conductivity, as well as havinginsular properties to prevent self-discharging during storage. Theelectrolyte can be either a liquid or a solid. A liquid electrolytecomprises a solvent and an alkali metal salt that together form anionically conducting liquid. So called “solid electrolytes” contain inaddition a matrix material that is used to separate the electrodes.

[0175] One preferred embodiment is a solid polymeric electrolyte, madeup of a solid polymeric matrix and a salt homogeneously dispersed via asolvent in the matrix. Suitable solid polymeric matrices include thosewell known in the art and include solid matrices formed from organicpolymers, inorganic polymers or a solid matrix-forming monomer and frompartial polymers of a solid matrix forming monomer.

[0176] In another variation, the polymer, solvent and salt together forma gel which maintains the electrodes spaced apart and provides the ionicconductivity between electrodes. In still another variation, theseparation between electrodes is provided by a glass fiber mat or othermatrix material and the solvent and salt penetrate voids in the matrix.

[0177] The electrolytes of the present invention comprise a saltdissolved in a mixture of an alkylene carbonate and a cyclic ester.Preferably, the salt of the electrolyte is a lithium or sodium salt.Such salts among those useful herein include LiAsF₆, LiPF₆, LiClO₄,LiB(C₆H₅)₄, LiAlCl₄, LiBr, LiBF₄, LiSO₃CF₃, LiN(SO₂CF₃)₂, LiN(SO₂C₂F₅)₂,and mixtures thereof, as well as sodium analogs, with the less toxicsalts being preferable. The salt content is preferably from about 5% toabout 65%, preferably from about 8% to about 35% (by weight ofelectrolyte). A preferred salt is LiBF₄. In a preferred embodiment, theLiBF₄ is present at a molar concentration of from 0.5M to 3M, preferably1.0M to 2.0M, and most preferably about 1.5M. Electrolyte compositionscomprising salts among those useful herein are described in U.S. Pat.No. 5,418,091, Gozdz et al., issued May 23, 1995; U.S. Pat. No.5,508,130, Golovin, issued Apr. 16, 1996; U.S. Pat. No. 5,541,020,Golovin et al., issued Jul. 30, 1996; U.S. Pat. No. 5,620,810, Golovinet al., issued Apr. 15, 1997; U.S. Pat. No. 5,643,695, Barker et al.,issued Jul. 1, 1997; U.S. Pat. No. 5,712,059, Barker et al., issued Jan.27, 1997; U.S. Pat. No. 5,851,504, Barker et al., issued Dec. 22, 1998;U.S. Pat. No. 6,020,087, Gao, issued Feb. 1, 2001; U.S. Pat. No.6,103,419, Saidi et al., issued Aug. 15, 2000; and PCT Application WO01/24305, Barker et al., published Apr. 5, 2001; all of which areincorporated by reference herein.

[0178] The electrolyte solvent contains a blend of a cyclic ester withan alkylene carbonate, an alkyl carbonate, or mixtures thereof. Thealkylene carbonates (cyclic carbonates) have a preferred ring size offrom 5 to 8. The carbon atoms of the ring may be optionally substitutedwith alkyl groups, preferably lower alkyl (C₁-C₆) chains. Examples ofunsubstituted cyclic carbonates are ethylene carbonate (5-memberedring), 1,3-propylene carbonate (6-membered ring), 1,4butylene carbonate(7-membered ring), and 1,5-pentylene carbonate (8-membered ring).Optionally the rings may be substituted with lower alkyl groups,preferably methyl, ethyl, propyl, or isopropyl groups. Such structuresare well known; examples include a methyl substituted 5-membered ring(also known as 1,2-propylene carbonate, or simply propylene carbonate(PC)), and a dimethyl substituted 5-membered ring carbonate (also knownas 2,3-butylene carbonate) and an ethyl substituted 5-membered ring(also known as 1,2-butylene carbonate or simply butylene carbonate (BC).Other examples include a wide range of methylated, ethylated, andpropylated 5-8 membered ring carbonates. In a preferred embodiment, thefirst component is a 5- or 6-membered ring carbonate. More preferably,the cyclic carbonate has a 5-membered ring. In a particular preferredembodiment, the alkylene carbonate comprises ethylene carbonate.

[0179] The alkyl carbonates are preferably C₁-C₆ alkyl, which may beunsubstituted or substituted on one or more carbon atoms with C₁-C₄alkyl. Alkyl carbonates among those useful herein include diethylcarbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC),ethyl methyl carbonate (EMC), and mixtures. DEC is a preferred alkylcarbonate.

[0180] The carbonate component of the electrolyte solvent may comprisean alkylene carbonate, an alkyl carbonate or mixtures thereof.Preferably, the carbonate is an alkylene carbonate.

[0181] The electrolyte solvent also comprises a cyclic ester, preferablya lactone. Preferred cyclic esters include those with ring sizes of 4 to7. The carbon atoms in the ring may be optionally substituted with alkylgroups, preferably lower alkyl (C₁-C₆) chains. Examples of unsubstitutedcyclic esters include the 4-membered β-propiolactone (or simplypropiolactone); γ-butyrolactone (5-membered ring), δ-valerolactone(6-membered ring) and ε-caprolactone (7-membered ring). Any of thepositions of the cyclic esters may be optionally substituted, preferablyby methyl, ethyl, propyl, or isopropyl groups. Thus, preferred secondcomponents include one or more solvents selected from the group ofunsubstituted, methylated, ethylated, or propylated lactones selectedfrom the group consisting of propiolacone, butyrolactone, valerolactone,and caprolactone. (It will be appreciated that some of the alkylatedderivatives of one lactone may be named as a different alkylatedderivative of a different core lactone. To illustrate, γ-butyrolactonemethylated on the γ-carbon may be named as γ-valerolactone.)

[0182] In a preferred embodiment, the cyclic ester of the secondcomponent has a 5- or a 6-membered ring. Thus, preferred secondcomponent solvents include one or more compounds selected fromγ-butyrolactone (gamma-butyrolactone), and δ-valerolactone, as well asmethylated, ethylated, and propylated derivatives. Preferably, thecyclic ester has a 5-membered ring. In a particular preferredembodiment, the second component cyclic ester comprises γ-butyrolactone.

[0183] The preferred two component solvent system contains the twocomponents in a weight ratio of from about 1:20 to a ratio of about20:1. More preferably, the ratios range from about 1:10 to about 10:1and more preferably from about 1:5 to about 5:1. In a preferredembodiment the cyclic ester is present in a higher amount than thecyclic carbonate. Preferably, at least about 60% (by weight) of the twocomponent system is made up of the cyclic ester, and preferably about70% or more. In a particularly preferred embodiment, the ratio of cyclicester to cyclic carbonate is about 3 to 1. In one embodiment, thesolvent system is made up essentially of γ-butyrolactone and ethylenecarbonate. A preferred solvent system thus contains about 3 parts byweight γ-butyrolactone and about 1 part by weight ethylene carbonate.The preferred salt and solvent are used together in a preferred mixturecomprising about 1.5 molar LiBF₄ in a solvent comprising about 3 partsγ-butyrolactone and about 1 part ethylene carbonate by weight.

[0184] The solvent optionally comprises additional solvents. Suchsolvents include low molecular weight organic solvents. The optionalsolvent is preferably a compatible, relatively non-volatile, aprotic,polar solvent. Examples of such optional solvents among those usefulherein include ethers such as diglyme, triglyme, and tetraglyme;dimethylsulfoxide, dioxolane, sulfolane, and mixtures thereof.

[0185] A separator allows the migration of ions while still providing aphysical separation of the electric charge between the electrodes, toprevent short-circuiting. The polymeric matrix itself may function as aseparator, providing the physical isolation needed between the anode andcathode. Alternatively, the electrolyte can contain a second oradditional polymeric material to further function as a separator. In apreferred embodiment, the separator prevents damage from elevatedtemperatures within the battery that can occur due to uncontrolledreactions preferably by degrading upon high temperatures to provideinfinite resistance to prevent further uncontrolled reactions.

[0186] A separator membrane element is generally polymeric and preparedfrom a composition comprising a copolymer. A preferred compositioncontains a copolymer of about 75% to about 92% vinylidene fluoride withabout 8% to about 25% hexafluoropropylene copolymer (availablecommercially from Atochem North America as Kynar FLEX) and an organicsolvent plasticizer. Such a copolymer composition is also preferred forthe preparation of the electrode membrane elements, since subsequentlaminate interface compatibility is ensured. The plasticizing solventmay be one of the various organic compounds commonly used as solventsfor electrolyte salts, e.g., propylene carbonate or ethylene carbonate,as well as mixtures of these compounds. Higher-boiling plasticizercompounds such as dibutyl phthalate, dimethyl phthalate, diethylphthalate, and tris butoxyethyl phosphate are preferred. Inorganicfiller adjuncts, such as fumed alumina or silanized fumed silica, may beused to enhance the physical strength and melt viscosity of a separatormembrane and, in some compositions, to increase the subsequent level ofelectrolyte solution absorption. In a non-limiting example, a preferredelectrolyte separator contains about two parts polymer per one part offumed silica.

[0187] A preferred battery comprises a laminated cell structure,comprising an anode layer, a cathode layer, and electrolyte/separatorbetween the anode and cathode layers. The anode and cathode layerscomprise a current collector. A preferred current collector is a coppercollector foil, preferably in the form of an open mesh grid. The currentcollector is connected to an external current collector tab. Suchstructures are disclosed in, for example, U.S. Pat. No. 4,925,752,Fauteux et al, issued May 15, 1990; U.S. Pat. No. 5,011,501, Shackle etal., issued Apr. 30, 1991; and U.S. Pat. No. 5,326,653, Chang, issuedJul. 5, 1994; all of which are incorporated by reference herein. In abattery embodiment comprising multiple electrochemical cells, the anodetabs are preferably welded together and connected to a nickel lead. Thecathode tabs are similarly welded and connected to a welded lead,whereby each lead forms the polarized access points for the externalload.

[0188] A preferred battery comprises a laminated cell structure,comprising an anode layer, a cathode layer, and electrolyte/separatorbetween the anode and cathode layers. The anode and cathode layerscomprise a current collector. A preferred current collector is a coppercollector foil, preferably in the form of an open mesh grid. The currentcollector is connected to an external current collector tab, for adescription of tabs and collectors. Such structures are disclosed in,for example, U.S. Pat. No. 4,925,752, Fauteux et al, issued May 15,1990; U.S. Pat. No. 5,011,501, Shackle et al., issued Apr. 30, 1991; andU.S. Pat. No. 5,326,653, Chang, issued Jul. 5, 1994; all of which areincorporated by reference herein. In a battery embodiment comprisingmultiple electrochemical cells, the anode tabs are preferably weldedtogether and connected to a nickel lead. The cathode tabs are similarlywelded and connected to a welded lead, whereby each lead forms thepolarized access points for the external load.

[0189] Lamination of assembled cell structures is accomplished byconventional means by pressing between metal plates at a temperature ofabout 120-160° C. Subsequent to lamination, the battery cell materialmay be stored either with the retained plasticizer or as a dry sheetafter extraction of the plasticizer with a selective low-boiling pointsolvent. The plasticizer extraction solvent is not critical, andmethanol or ether are often used.

[0190] In a preferred embodiment, an electrode membrane comprising theelectrode active material (e.g., an insertion material such as carbon orgraphite or a insertion compound) is dispersed in a polymeric bindermatrix. The electrolyte/separator film membrane is preferably aplasticized copolymer, comprising a polymeric separator and a suitableelectrolyte for ion transport. The electrolyte/separator is positionedupon the electrode element and is covered with a positive electrodemembrane comprising a composition of a finely divided lithium insertioncompound in a polymeric binder matrix. An aluminum collector foil orgrid completes the assembly. A protective bagging material covers thecell and prevents infiltration of air and moisture.

[0191] In another embodiment, a multi-cell battery configuration may beprepared with copper current collector, a negative electrode, anelectrolyte/separator, a positive electrode, and an aluminum currentcollector. Tabs of the current collector elements form respectiveterminals for the battery structure.

[0192] In a preferred embodiment of a lithium-ion battery, a currentcollector layer of aluminum foil or grid is overlaid with a positiveelectrode film, or membrane, separately prepared as a coated layer of adispersion of insertion electrode composition. This is preferably aninsertion compound such as the active material of the present inventionin powder form in a copolymer matrix solution, which is dried to formthe positive electrode. An electrolyte/separator membrane is formed as adried coating of a composition comprising a solution containing VdF:HFPcopolymer and a plasticizer solvent is then overlaid on the positiveelectrode film. A negative electrode membrane formed as a dried coatingof a powdered carbon or other negative electrode material dispersion ina VdF:HFP copolymer matrix solution is similarly overlaid on theseparator membrane layer. A copper current collector foil or grid islaid upon the negative electrode layer to complete the cell assembly.Therefore, the VdF:HFP copolymer composition is used as a binder in allof the major cell components, positive electrode film, negativeelectrode film, and electrolyte/separator membrane. The assembledcomponents are then heated under pressure to achieve heat-fusion bondingbetween the plasticized copolymer matrix electrode and electrolytecomponents, and to the collector grids, to thereby form an effectivelaminate of cell elements. This produces an essentially unitary andflexible battery cell structure.

[0193] Cells comprising electrodes, electrolytes and other materialsamong those useful herein are described in the following documents, allof which are incorporated by reference herein: U.S. Pat. No. 4,668,595,Yoshino et al., issued May 26, 1987; U.S. Pat. No. 4,792,504, Schwab etal., issued Dec. 20, 1988; U.S. Pat. No. 4,830,939, Lee et al., issuedMay 16, 1989; U.S. Pat. No. 4,935,317, Fauteaux et al., issued Jun. 19,1980; U.S. Pat. No. 4,990,413, Lee et al., issued Feb. 5, 1991; U.S.Pat. No. 5,037,712, Shackle et al., issued Aug. 6, 1991; U.S. Pat. No.5,262,253, Golovin, issued Nov. 16, 1993; U.S. Pat. No. 5,300,373,Shackle, issued Apr. 5, 1994; U.S. Pat. No. 5,399,447, Chaloner-Gill, etal., issued Mar. 21, 1995; U.S. Pat. No. 5,411,820, Chaloner-Gill,issued May 2, 1995; U.S. Pat. No. 5,435,054, Tonder et al., issued Jul.25, 1995; U.S. Pat. No. 5,463,179, Chaloner-Gill et al., issued Oct. 31,1995; U.S. Pat. No. 5,482,795, Chaloner-Gill., issued Jan. 9, 1996; U.S.Pat. No. 5,660,948, Barker, issued Sep. 16, 1995; and U.S. Pat. No.6,306,215, Larkin, issued Oct. 23, 2001. A preferred electrolyte matrixcomprises organic polymers, including VdF:HFP. Examples of casting,lamination and formation of cells using VdF:HFP are as described in U.S.Pat. Nos. 5,418,091, Gozdz et al., issued May 23, 1995; U.S. Pat. No.5,460,904, Gozdz et al., issued Oct. 24, 1995; U.S. Pat. No. 5,456,000,Gozdz et al., issued Oct. 10, 1995; and U.S. Pat. No. 5,540,741, Gozdzet al., issued Jul. 30, 1996; all of which are incorporated by referenceherein.

[0194] The electrochemical cell architecture is typically governed bythe electrolyte phase. A liquid electrolyte battery generally has acylindrical shape, with a thick protective cover to prevent leakage ofthe internal liquid. Liquid electrolyte batteries tend to be bulkierrelative to solid electrolyte batteries due to the liquid phase andextensive sealed cover. A solid electrolyte battery, is capable ofminiaturization, and can be shaped into a thin film. This capabilityallows for a much greater flexibility when shaping the battery andconfiguring the receiving apparatus. The solid state polymer electrolytecells can form flat sheets or prismatic (rectangular) packages, whichcan be modified to fit into the existing void spaces remaining inelectronic devices during the design phase.

[0195] The following non-limiting examples illustrate the compositionsand methods of the present invention.

EXAMPLE 1

[0196] An electrode active material of formulaLi_(0.025)Cu_(0.9)Al_(0.025)Mg_(0.05)PO₄, is made as follows. Thefollowing sources of Li, Co, Al, Mg, and phosphate are providedcontaining the respective elements in a molar ratio of1.025:0.9:0.025:0.05:1. 0.05125 moles Li₂CO₃ (mol. wt. 73.88 g/mol) 3.8g 0.03 moles Co₃O₄ (240.8 g/mol) 7.2 g 0.0025 moles Al(OH)₃ (78 g/mol)0.195 g 0.005 moles Mg(OH)₂ (58 g/mol) 0.29 g 0.1 moles (NH₄)₂HPO₄ (132g/mol) 13.2 g 0.2 moles elemental carbon (12 g/mol) (>100% excess) 2.4 g

[0197] The above starting materials are combined and ball milled to mixthe particles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure. An electrode is made with 80% of the active material,10% of Super P conductive carbon, and 10% poly vinylidene difluoride. Acell with that electrode as cathode and lithium metal as anode isconstructed with an electrolyte comprising 1 M LiBF₄ dissolved in a 3:1by weight mixture of γ-butyrolactone:ethylene carbonate. The activematerial exhibits a reversible capacity over 140 mAhg-1.

EXAMPLE 2

[0198] An electrode active material of formulaLi_(1.025)Co_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄(LiCo_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)Li_(0.025)PO₄) is made asfollows. The following sources of Li, Co, Fe, Al, Mg, and phosphate areprovided containing the respective elements in a molar ratio of1.025:0.85:0.05:0.025:0.05:1. 0.05125 moles Li₂CO₃ (mol. wt. 73.88g/mol) 3.8 g 0.02833 moles Co₃O₄ (240.8 g/mol) 6.82 g 0.0025 moles Fe₂O₃(159.7 g/mol) 0.4 g 0.0025 moles Al(OH)₃ (78 g/mol) 0.195 g 0.005 molesMg(OH)₂ (58 g/mol) 0.29 g 0.1 moles (NH₄)₂HPO₄ (132 g/mol) 13.2 g 0.2moles elemental carbon (12 g/mol) (>100% excess) 2.4 g

[0199] The above starting materials are combined and ball milled to mixthe particles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure. An electrode is made with 80% of the active material,10% of Super P conductive carbon, and 10% poly vinylidene difluoride. Acell with that electrode as cathode and a carbon intercalation anode isconstructed with an electrolyte comprising 1 M LiPF₆ dissolved in a2:1:1 by weight mixture of γ-butyrolactone:ethylene carbonate:dimethylcarbonate.

EXAMPLE 3

[0200] An electrode active material of the formulaLi_(1.025)Cu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO₄(LiCu_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)Li_(0.025)PO₄) is made as follows.The following sources of Li, Co, Fe, Al, Mg, and phosphate are providedcontaining the respective elements in a molar ratio of1.025:0.8:0.1:0.025:0.05:1. 0.05125 moles Li₂CO₃ (mol. wt. 73.88 g/mol)3.8 g 0.02667 moles Co₃O₄ (240.8 g/mol) 6.42 g 0.005 moles Fe₂O₃ (159.7g/mol) 0.8 g 0.0025 moles Al(OH)₃ (78 g/mol) 0.195 g 0.005 moles Mg(OH)₂(58 g/mol) 0.29 g 0.1 moles (NH₄)₂HPO₄ (132 g/mol) 13.2 g 0.2 moleselemental carbon (12 g/mol) (>100% excess) 2.4 g

[0201] The above starting materials are combined and ball milled to mixthe particles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure. An electrode is made with 80% of the active material,10% of Super P conductive carbon, and 10% poly vinylidene difluoride. Acell with that electrode as cathode and a carbon intercalation anode isconstructed with an electrolyte comprising 1 M LiPF₆ dissolved in a 3:1by weight mixture of γ-butyrolactone:ethylene carbonate.

EXAMPLE 4

[0202] An electrode active material of the formulaLiCo_(0.8)Fe_(0.05)Al_(0.1)Mg_(0.05)(PO₄)_(0.9)(SiO₄)_(0.1) is made asfollows. The following sources of Li, Co, Fe, Al, Mg, phosphate, andsilicate are provided containing the respective elements in a molarratio of 1:0.8:0.05:0.1:0.05:0.9:0.1. 0.05 moles Li₂CO₃ (mol. wt. 73.88g/mol) 3.7 g 0.08 moles CoCO₃ (118.9 g/mol) 9.5 g 0.0025 moles Fe₂O₃(159.7 g/mol) 0.4 g 0.0025 moles Al(OH)₃ (78 g/mol) 0.195 g 0.005 molesMg(OH)₂ (58 g/mol) 0.29 g 0.09 moles (NH₄)₂HPO₄ (132 g/mol) 11.9 g 0.01moles SiO₂ (60.1 g/mol) 0.6 g 0.2 moles elemental carbon (12 g/mol)(excess) 2.4 g

[0203] The above amounts of starting materials are combined and ballmilled to mix the particles. Note that the reducing carbon is present inapproximately a 40-fold excess, relative to the 0.05 moles of iron inthe iron III oxide to be reduced. Thereafter, the particle mixture ispelletized. The pelletized mixture is heated for 4-20 hours at 750° C.in an oven in an argon atmosphere. The sample is removed from the ovenand cooled. An electrode is made with 80% of the active material, 10% ofSuper P conductive carbon, and 10% polyvinylidene difluoride. A cellwith that electrode as cathode and a carbon intercalation anode isconstructed with an electrolyte comprising 1 M LiBF₄ dissolved in 3:1 byweight mixture of γ-butyrolactone:ethylene carbonate.

EXAMPLE 5

[0204] An electrode active material of the formulaLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) is made asfollows. The following sources containing Li, Co, Fe, Al, Mg, phosphate,and fluoride are provided containing the respective elements in a molarratio of 1.0:0.8:0.1:0.025:0.05:1.0:0.025. 0.05 moles Li₂CO₃ (mol. wt.73.88 g/mol), 0.1 mol Li 3.7 g 0.02667 moles Co₃O₄ (240.8 g/mol), 0.08mol Co 6.42 g 0.005 moles Fe₂O₃ (159.7 g/mol), 0.01 mol Fe 0.8 g 0.0025moles Al(OH)₃ (78 g/mol), 0.0025 mol Al 0.195 g 0.005 moles Mg(OH)₂ (58g/mol), 0.005 mol Mg 0.29 g 0.1 moles (NH₄)₂HPO₄ (132 g/mol), 0.1 molphosphate 13.2 g 0.00125 moles NH₄HF₂ (57 g/mol), 0.0025 mol F 0.071 g0.2 moles elemental carbon (12 g/mol) (>100% excess) 2.4 g

[0205] The above starting materials are combined and ball milled to mixthe particles. Thereafter, the particle mixture is pelletized. Thepelletized mixture is heated for 4-20 hours at 750° C. in an oven in anargon atmosphere. The sample is removed from the oven and cooled. Anx-ray diffraction pattern shows that the material has an olivine typecrystal structure. An electrode is made with 80% of the active material,10% of Super P conductive carbon, and 10% polyvinylidene difluoride. Acell with that electrode as cathode and a carbon intercalation anode isconstructed with an electrolyte comprising 1M LiBF₄ dissolved in a 3:1mixture by weight of γ-butyrolactone:propylene carbonate.

EXAMPLE 6

[0206] An electrode active material of the formula LiFe_(0.9)Mg_(0.1)PO₄is made according to the following reaction scheme.

0.50Li₂CO₃+0.45Fe₂O₃+0.10Mg(OH)₂+(NH₄)₂HPO₄+0.45C→LiFe_(0.9)Mg_(0.1)PO₄+0.50CO₂+0.45CO+2.0NH₃+1.6H₂O

[0207] A mixture of 36.95 g (0.50 mol) of Li₂CO₃, 71.86 g (0.45 mol) ofFe₂O₃, 5.83 g (0.10 mol) of 0.10 Mg(OH)₂, 132.06 g (1.0 mol) of(NH₄)₂HPO₄, and 10.8 g (0.90 g-mol, 100% excess) of carbon is made,using a mortar and pestle. The mixture is pelletized, and transferred toa temperature-controlled tube furnace equipped with an argon gas flow.The mixture is heated at a ramp rate of about 2° C./minute to anultimate temperature of about 750° C. in the inert atmosphere andmaintained at this temperature for about 8 hours. The product is thencooled to ambient temperature (about 22° C.). An electrode is made with80% of the active material, 10% of Super P conductive carbon, and 10%polyvinylidene difluoride. A cell with that electrode as cathode and acarbon intercalation anode is constructed with an electrolyte comprising1M LiBF₄ dissolved in a 4:1 mixture by weight of6-valerolactone:ethylene carbonate.

EXAMPLE 7

[0208] An electrode active material comprisingLi_(1.25)Fe_(0.9)Mg_(0.1)PO₄F_(0.25) is made according to the followingreaction scheme.

1.0LiFe_(0.9)Mg_(0.1)PO₄ +dLiF→Li_(1+d)Fe_(0.9)Mg_(0.1)PO₄F_(d)

[0209] For d equal to 0.25, 1.082 grams of LiFe_(0.9)Mg_(0.1)PO₄ (madeas in Example 6) and 0.044 grams of LiF are premixed and pelletized,transferred to an oven and heated to an ultimate temperature of 700° C.and maintained for 15 minutes at this temperature. The sample is cooledand removed from the oven. Almost no weight loss is recorded for thereaction, consistent with full incorporation of the lithium fluorideinto the phosphate structure to make an active material of formulaLi_(1.25)Fe_(0.9)Mg_(0.1)PO₄F_(0.25). An electrode is made with 80% ofthe active material, 10% of Super P conductive carbon, and 10%polyvinylidene difluoride. A cell with that electrode as cathode and acarbon intercalation anode is constructed with an electrolyte comprising1M LiBF₄ dissolved in a 3:1 mixture by weight ofγ-butyrolactone:ethylene carbonate.

EXAMPLE 8

[0210] An electrode active material comprising NaVPO₄F is made accordingto the following reaction scheme.

0.5Na₂CO₃+NH₄F+VPO₄→NaVPO₄F+NH₃+0.5CO₂+0.5H₂O

[0211] 1.23 grams Of VPO₄, 0.31 grams of NH₄F, and 0.45 grams Na₂CO₃ arepremixed with approximately 20 milliliters of deionized water andtransferred and sealed in a Parr Model 4744 acid digestion bomb, whichis a Teflon lined stainless steel reaction vessel. The bomb is placed inan oven and heated to an ultimate temperature of 250° C. and maintainedat this temperature for forty-eight hours. The sample is cooled to roomtemperature and removed for analysis. The sample is washed repeatedlywith the deionized water to remove unreacted impurities and thereafteris dried in an argon atmosphere at 250° C. for an hour.

EXAMPLE 9

[0212] An electrode active material comprisingLi_(2.025)Co_(0.9)Al_(0.025)Mg_(0.05)PO₄F is made as follows. (ThisExample shows the synthesis of a mixed metal active material containinglithium and three different metals, with two metals in a +2 and onemetal in a +3 oxidation state). For A=Li, a=2.025, M¹=Co, M²=Al, andM³=Mg, the reaction proceeds according to the following scheme.0.5125  Li₂CO₃ + 0.3  Co₃(Po₄)₂ ⋅ 8H₂O + 0.0125  A1₂O₃ + 0.05  Mg(OH)₂ + LiF + 0.4  NH₄H₂PO₄ → Li_(2.025)Co_(0.9)A1_(0.025)Mg_(0.05)PO₄F + 0.5125CO₂ + 0.4  NH₃ + 8.9H₂O.

[0213] Powdered starting materials are provided in the molar ratiosindicated, mixed, pelletized, and heated in an oven at 750° C. for fourhours to produce a reaction product. An electrode is made with 80% ofthe active material, 10% of Super P conductive carbon, and 10%polyvinylidene difluoride. A cell with that electrode as cathode and acarbon intercalation anode is constructed with an electrolyte comprising1M LiBF₄ dissolved in a 3:2 mixture by weight ofβ-propiolactone:ethylene carbonate.

EXAMPLE 10

[0214] An electrode active material comprising Li₆V₂(PO₄)₃F issynthesized according to the equation

3C+2.5Li₂CO₃+V₂O₅+LiF+3NH₄H₂PO₄→Li₆V₂(PO₄)₃F+2.5CO₂+3NH₃+4.5H₂O+3CO.

[0215] The equation presupposes that the carbothermal reaction proceedswith production of carbon monoxide. The carbon is provided in excess, inthis case to reduce the vanadium +5 species all the way down to itslowest oxidation of +2. It is appreciated in the reaction scheme thatsuch a reduction is possible because there is enough lithium in thereaction scheme that lithium is incorporated into the reaction productin an amount sufficient to neutralize the [(PO₄)₃F]¹⁰⁻ group of theactive material. An electrode is made with 80% of the active material,10% of Super P conductive carbon, and 10% polyvinylidene difluoride. Acell with that electrode as cathode and a carbon intercalation anode isconstructed with an electrolyte comprising 1M LiBF₄ dissolved in a 3:1mixture by weight of γ-butyrolactone:ethylene carbonate.

[0216] The examples and other embodiments described herein are exemplaryand not intended to be limiting in describing the full scope ofcompositions and methods of this invention. Equivalent changes,modifications and variations of specific embodiments, materials,compositions and methods may be made within the scope of the presentinvention, with substantially similar results.

What is claimed is:
 1. A lithium battery comprising: (a) a firstelectrode comprising an active material of the formulaA_(a)M_(b)(XY₄)_(c)Z_(d), wherein (i) A is selected from the groupconsisting of Li, Na, K, and mixtures thereof, and 0<a ≦9; (ii) M is oneor more metals, comprising at least one metal which is capable ofundergoing oxidation to a higher valence state, and 1≦b≦3; (iii) XY₄ isselected from the group consisting of X′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y),X″S₄, and mixtures thereof, where X′ is selected from the groupconsisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof; X″ isselected from the group consisting of P, As, Sb, Si, Ge, V and mixturesthereof; Y′ is selected from the group consisting of halogen, S, N, andmixtures thereof; 0≦x≦3; and 0<y≦2; and 0<c≦3; (iv) Z is OH, halogen, ormixtures thereof, and 0≦d≦6; and wherein M, XY₄, Z, a, b, c, d, x and yare selected so as to maintain electroneutrality of said compound; (b) asecond electrode which is a counter-electrode to said first electrode;and (c) an electrolyte comprising a mixture of a cyclic ester and acarbonate selected from the group consisting of alkyl carbonates,alkylene carbonates, and mixtures thereof.
 2. A battery according toclaim 1, wherein c is about
 1. 3. A battery according to claim 2,wherein A comprises Li, and 0.1≦a≦2, and said active material has anolivine structure.
 4. A battery according to claim 1, wherein c is about3, and said active material has a NASICON structure.
 5. A batteryaccording to claim 1, wherein M comprises M′_(1-m)M″_(m), where M′ is atleast one element from Groups 4 to 11 of the Periodic Table; M″ is atleast one element from Groups 2, 3, and 12-16 of the Periodic Table; and0<m<1.
 6. A battery according to claim 5, wherein M′ is selected fromthe group consisting of Fe, Co, Ni, Mn, Cu, V, Zr, Ti, Cr, and mixturesthereof.
 7. A battery according to claim 6, wherein M′ is selected fromthe group consisting of Fe, Co, Mn, Ti, and mixtures thereof.
 8. Abattery according to claim 5, wherein M′ comprises Fe and Co.
 9. Abattery according to claim 8, wherein M″ is selected from the groupconsisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, Al, and mixturesthereof.
 10. A battery according to claim 9, wherein M″ is selected fromthe group consisting of Mg, Ca, Al, and mixtures thereof.
 11. A batteryaccording to claim 1, wherein X′ comprises Si or a mixture of Si and P,and X″ comprises Si or a mixture of Si and P.
 12. A battery according toclaim 1, wherein XY₄ is selected from the group consisting OfX′O_(4-x)Y′_(x), X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′is P and X″ is P; and 0<x<3; and 0<y<4.
 13. A battery according to claim12, wherein XY₄ is PO_(4-x)F_(x), and 0<x≦1.
 14. A battery according toclaim 1, wherein Z comprises F, and 0.1<d≦4.
 15. A battery according toclaim 1, wherein said carbonate comprises an alkylene carbonate having aring size of from 5 to 8 atoms and is unsubstituted or substituted withlower alkyl on one or more carbon atoms.
 16. A battery according toclaim 1, wherein said carbonate comprises a C₁-C₆ alkyl carbonate whichis unsubstituted or substituted with C₁-C₄ alkyl on one or more carbonatoms.
 17. A battery according to claim 1, wherein said cyclic ester hasa ring size of from 4 to 7 atoms, and is unsubstituted or substituted onone or more carbon atoms with a lower alkyl group.
 18. A batteryaccording to claim 17, wherein said carbonate comprises an alkylenecarbonate, and the weight ratio of said cyclic ester to said alkylenecarbonate is from about 1:1 to about 5:1.
 19. A battery according toclaim 18, wherein said carbonate additionally comprises an alkylcarbonate.
 20. A battery according to claim 18, wherein said carbonateis ethylene carbonate and said cyclic ester is γ-butyrolactone.
 21. Abattery comprising: (a) a first electrode comprising an active materialof the formula Li_(a)M_(b)(PO₄)Z_(d), wherein (i) 0.1<a≦4; (ii) M is oneor more metals, comprising at least one metal which is capable ofundergoing oxidation to a higher valence state, and 1≦b≦3; and (iii) Zis halogen, and 0.1<d≦4; and wherein M, Z, a, b, and d are selected soas to maintain electroneutrality of said compound; (b) a secondelectrode which is a counter-electrode to said first electrode; and (c)an electrolyte comprising a mixture of a cyclic ester and a carbonateselected from the group consisting of alkyl carbonates, alkylenecarbonates, and mixtures thereof.
 22. A battery according to claim 21,wherein 0.2≦a≦1.
 23. A battery according to claim 22, wherein Mcomprises M′_(1-m)M″_(m), where M′ is at least one element from Groups 4to 11 of the Periodic Table; M″ is at least one element from Groups 2,3, and 12-16 of the Periodic Table; and 0<m<1.
 24. A battery accordingto claim 23, wherein M′ is selected from the group consisting of Fe, Co,Mn, Cu, V, Cr, and mixtures thereof, and M″ is selected from the groupconsisting of Mg, Ca, Zn, Ba, Al, and mixtures thereof.
 25. A batteryaccording to claim 21, wherein said carbonate comprises an alkylenecarbonate having a ring size of from 5 to 8 atoms and is unsubstitutedor substituted with lower alkyl on one or more carbon atoms.
 26. Abattery according to claim 21, wherein said carbonate comprises a C₁-C₆alkyl carbonate which is unsubstituted or substituted with C₁-C₄ alkylon one or more carbon atoms.
 27. A battery according to claim 25,wherein said cyclic ester has a ring size of from 4 to 7 atoms, and isunsubstituted or substituted on one or more carbon atoms with a loweralkyl group.
 28. A battery according to claim 26, wherein said alkylenecarbonate is ethylene carbonate, said cyclic ester is γ-butyrolactone,and the weight ratio of said cyclic ester to said alkylene carbonate isfrom about 1:1 to about 5:1.
 29. A battery comprising: (a) a firstelectrode comprising an active material of the formulaLi_(a)Co_(e)Fe_(f)M¹ _(g)M² _(h)M³ _(i)XY₄ wherein (i) 0<a≦2, e>0, andf>0; (ii) M¹ is one or more transition metals, where g≧0; (iii) M² isone or more +2 oxidation state non-transition metals, where h≧0; (iv) M³is one or more +3 oxidation state non-transition metals, where i≧0; and(v) XY₄ is selected from the group consisting of X′O_(4-x)Y′_(x),X′O_(4-y)Y′_(2y), X″S₄, and mixtures thereof, where X′ is selected fromthe group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof;X″ is selected from the group consisting of P, As, Sb, Si, Ge, V andmixtures thereof; Y′ is selected from the group consisting of halogen,S, N, and mixtures thereof; 0≦x≦3; and 0<y≦2; and wherein (e+f+g+h+i)<2,and M¹, M², M³, XY₄, a, e, f, g, h, i, x, and y are selected so as tomaintain electroneutrality of said compound; and (b) a second electrodewhich is a counter-electrode to said first electrode; and (c) anelectrolyte comprising an electrolyte salt, a cyclic ester and acarbonate selected from the group consisting of alkyl carbonates,alkylene carbonates, and mixtures thereof.
 30. A battery according toclaim 29, wherein 0.8≦(e+f+g+h+i)≦1.2.
 31. A battery according to claim30, wherein 0.9≦(e+f+g+h+i)≦1.
 32. A battery according to claim 30,wherein e≧0.5.
 33. A battery according to claim 32, wherein e≧0.8.
 34. Abattery according to claim 31, wherein 0.01≦f≦0.5.
 35. A batteryaccording to claim 34, wherein 0.05≦f≦0.15.
 36. A battery according toclaim 31, wherein 0.01≦g≦0.5.
 37. A battery according to claim 36,wherein 0.05≦g≦0.2.
 38. A battery according to claim 36, wherein M¹ isselected from the group consisting of Ti, V, Cr, Mn, Ni, Cu and mixturesthereof.
 39. A battery according to claim 38, wherein M¹ is selectedfrom the group consisting of Mn, Ti, and mixtures thereof.
 40. A batteryaccording to claim 31, wherein (h+i)>0.
 41. A battery according to claim40, wherein 0.01≦(h+i)≦0.5.
 42. A battery according to claim 41, wherein0.02≦(h+i)≦0.3.
 43. A battery according to claim 41, wherein 0.01≦h≦0.2.44. A battery according to claim 43, wherein 0.01≦h≦0.1.
 45. A batteryaccording to claim 43, wherein M² is selected from the group consistingof Be, Mg, Ca, Sr, Ba, and mixtures thereof.
 46. A battery according toclaim 45, wherein M² is Mg.
 47. A battery according to claim 41, wherein0.01≦i≦0.2.
 48. A battery according to claim 47, wherein 0.01≦i≦0.1. 49.A battery according to claim 47, wherein M is selected from the groupconsisting of B, Al, Ga, In and mixtures thereof.
 50. A batteryaccording to claim 49, wherein M³ is Al.
 51. A battery according toclaim 29, wherein XY₄ is PO₄.
 52. A battery according to claim 51,wherein e≧0.8, and 0.05≦f≦0.15.
 53. A battery according to claim 52,wherein 0.01≦h≦0.1.
 54. A battery according to claim 53, wherein M² isselected from the group consisting of Be, Mg, Ca, Sr, Ba, and mixturesthereof.
 55. A battery according to claim 52, wherein 0.01≦i≦0.1.
 56. Abattery according to claim 55, wherein M³ is Al.
 57. A battery accordingto claim 29, wherein XY₄ is PO_(4-x)F_(x), and 0<x≦1.
 58. A batteryaccording to claim 57, wherein 0.01≦x≦0.05.
 59. A battery according toclaim 57, wherein e≧0.8, and 0.05≦f≦0.15.
 60. A battery according toclaim 59, wherein 0.01≦h≦0.1.
 61. A battery according to claim 60,wherein M² is selected from the group consisting of Be, Mg, Ca, Sr, Ba,and mixtures thereof.
 62. A battery according to claim 59, wherein0.01≦i≦0.1.
 63. A battery according to claim 62, wherein M³ is Al.
 64. Abattery according to claim 29, wherein said carbonate comprises analkylene carbonate having a ring size of from 5 to 8 atoms and isunsubstituted or substituted with lower alkyl on one or more carbonatoms.
 65. A battery according to claim 64, wherein said alkylenecarbonate is selected from the group consisting of ethylene carbonate,1,3-propylene carbonate, 1,4-butylene carbonate, 1,5-pentylenecarbonate, 1,2-propylene carbonate, 2,3-butylene carbonate, 1,2-butylenecarbonate, and mixtures thereof.
 66. A battery according to claim 65,wherein said alkylene carbonate is ethylene carbonate.
 67. A batteryaccording to claim 29, wherein said carbonate comprises a C₁-C₆ alkylcarbonate which is unsubstituted or substituted with C₁-C₄ alkyl on oneor more carbon atoms.
 68. A battery according to claim 67, wherein saidalkyl carbonate is selected from the group consisting of diethylcarbonate, ethyl methyl carbonate, dimethyl carbonate, and mixturesthereof.
 69. A battery according to claim 66, wherein said cyclic esterhas a ring size of from 4 to 7 atoms, and is unsubstituted orsubstituted on one or more carbon atoms with a lower alkyl group.
 70. Abattery according to claim 69, wherein said cyclic ester is selectedfrom the group consisting of substituted or unsubstitutedβ-propiolactone; substituted or unsubstituted γ-butyrolactone,substituted or unsubstituted δ-valerolactone, substituted orunsubstituted ε-caprolactone, and mixtures thereof.
 71. A batteryaccording to claim 69, wherein said cyclic ester is γ-butyrolactone. 72.A battery according to claim 29, wherein said electrolyte salt is alithium salt selected from the group consisting of LiAsF₆, LiPF₆,LiClO₄, LiB(C₆H₅)₄, LiAlCl₄, LiBr, LiBF₄, LiSO₃CF₃, LiN(SO₂CF₃)₂,LiN(SO₂C₂F₅)₂, and mixtures thereof.
 73. A battery according to claim72, wherein said salt is LiBF₄.
 74. A battery according to claim 29,wherein said cyclic ester comprises at least about 60% of saidelectrolyte, and the weight ratio of said cyclic ester to said alkylenecarbonate is from about 1:1 to about 5:1.
 75. A battery according toclaim 74, wherein said weight ratio is about 3:1.
 76. A lithium batteryof claim 29, wherein said first electrode is a cathode, and said secondelectrode is an insertion anode.
 77. A lithium battery of claim 76,wherein said second electrode comprises a material selected from thegroup consisting of metal oxides, metal chalcogenides, carbon, graphite,and mixtures thereof.
 78. A battery comprising: (a) a first electrodecomprising an active material having an olivine structure, of theformula LiM(PO_(4-x)Y′_(x)) wherein M is M¹ _(g)M² _(h)M³ _(i)M⁴ _(j),and (i) M¹ is one or more transition metals; (ii) M² is one or more +2oxidation state non-transition metals; (iii) M³ is one or more +3oxidation state non-transition metals, (iv) M⁴ is one or more +1oxidation state non-transition metals; (v) Y′ is halogen; and g>0, eachof h, i, and j≧0; (g+h+i+j)≦1, and 0≦x≦0.5; and (b) a second electrodewhich is a counter-electrode to said first electrode; and (c) anelectrolyte comprising an electrolyte salt, an alkylene carbonate, and acyclic ester and a carbonate selected from the group consisting of alkylcarbonates, alkylene carbonates, and mixtures thereof.
 79. An electrodeactive material according to claim 78, wherein g≧0.8.
 80. An electrodeactive material according to claim 79, wherein g≧0.9.
 81. An electrodeactive material according to claim 79, wherein M¹ is a +2 oxidationstate transition metal selected from the group consisting of V, Cr, Mn,Fe, Co, Ni, and mixtures thereof.
 82. An electrode active materialaccording to claim 81, wherein M¹ is selected from the group consistingof Fe, Co, and mixtures thereof.
 83. An electrode active materialaccording to claim 79, wherein (h+i)>0.
 84. An electrode active materialaccording to claim 83, wherein 0.01≦(h+i)≦0.5.
 85. An electrode activematerial according to claim 84, wherein 0.02≦(h+i)≦0.3.
 86. An electrodeactive material according to claim 83, wherein 0.01≦h≦0.2.
 87. Anelectrode active material according to claim 86, wherein 0.01≦h≦0.1. 88.An electrode active material according to claim 86, wherein M² isselected from the group consisting of Be, Mg, Ca, Sr, Ba, and mixturesthereof.
 89. An electrode active material according to claim 83, wherein0.01≦i≦0.2.
 90. An electrode active material according to claim 89,wherein 0.01≦i≦0.1.
 91. An electrode active material according to claim89, wherein M³ is Al.
 92. An electrode active material according toclaim 79, wherein j=0.
 93. An electrode active material according toclaim 79, wherein 0.01≦j≦0.1.
 94. An electrode active material accordingto claim 93, wherein M⁴ is selected from the group consisting of Li, Na,and K.
 95. An electrode active material according to claim 94, whereinM⁴ is Li.
 96. An electrode active material according to claim 79,wherein x=0.
 97. An electrode active material according to claim 96,wherein g≧0.8, and (g+h+i+j)=1.
 98. An electrode active materialaccording to claim 97, wherein 0.01≦h≦0.1 and M² is selected from thegroup consisting of Be, Mg, Ca, Sr, Ba, and mixtures thereof.
 99. Anelectrode active material according to claim 97, wherein 0.01≦i≦0.1, andM³ is Al.
 100. An electrode active material according to claim 97,wherein 0.01≦j≦0.1, and M⁴ is Li.
 101. An electrode active materialaccording to claim 78, wherein 0<x≦1.
 102. An electrode active materialaccording to claim 101, wherein 0.01≦x≦0.05, and (g+h+i+j)<1.
 103. Anelectrode active material according to claim 102, wherein g≧0.8.
 104. Anelectrode active material according to claim 103, wherein 0.01≦h≦0.1,and M² is selected from the group consisting of Be, Mg, Ca, Sr, Ba, andmixtures thereof.
 105. An electrode active material according to claim103, wherein 0.01≦i≦0.1, and M³ is Al.
 106. An electrode active materialaccording to claim 103, wherein j=0.
 107. An electrode active materialaccording to claim 106, wherein (g+h+i)=1-x.
 108. A battery according toclaim 81, wherein said active material is selected from the groupconsisting of: LiFePO₄; LiFe_(0.9)Mg_(0.1)PO₄; LiFe_(0.8)Mg_(0.2)PO₄;Li_(1.025)Cu_(0.85)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.80)Fe_(0.10)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.75)Fe_(0.05)Al_(0.025)Mg_(0.05)PO₄,Li_(1.025)Co_(0.7)(Fe_(0.4)Mn_(0.6))_(0.2)Al_(0.025)Mg_(0.05)PO₄,LiCo_(0.8)Fe_(0.1)Al_(0.025)Ca_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025),LiCo_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.05)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Al_(0.025)PO₄;Li_(1.025)Co_(0.8)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO_(3.975)F_(0.025);LiCu_(0.825)Fe_(0.1)Ti_(0.025)Mg_(0.025)PO₄;LiCu_(0.85)Fe_(0.075)Ti_(0.025)Mg_(0.025)PO₄; and mixtures thereof. 109.A battery according to claim 29, wherein said active material isLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025).
 110. A batteryaccording to claim 80, wherein said carbonate comprises an alkylenecarbonate having a ring size of from 5 to 8 atoms and is unsubstitutedor substituted with lower alkyl on one or more carbon atoms.
 111. Abattery according to claim 110, wherein said alkylene carbonate isethylene carbonate.
 112. A battery according to claim 80, wherein saidcarbonate comprises C₁-C₆ alkyl carbonate which is unsubstituted orsubstituted with C₁-C₄ alkyl on one or more carbon atoms.
 113. A batteryaccording to claim 112, wherein said alkyl carbonate is diethylcarbonate.
 114. A battery according to claim 80, wherein said cyclicester has a ring size of from 4 to 7 atoms, and is unsubstituted orsubstituted on one or more carbon atoms with a lower alkyl group.
 115. Abattery according to claim 114, wherein said cyclic ester isγ-butyrolactone.
 116. A battery according to claim 80, wherein said saltis selected from the group consisting of LiAsF₆, LiPF₆, LiClO₄,LiB(C₆H₅)₄, LiAlCl₄, LiBr, LiBF₄, LiSO₃CF₃, LiN(SO₂CF₃)₂, LiN(SO₂C₂F₅)₂,and mixtures thereof.
 117. A battery according to claim 80, wherein theweight ratio of said cyclic ester to said alkylene carbonate is fromabout 1:1 to about 5:1.
 118. A battery according to claim 117, whereinsaid weight ratio is about 3:1.
 119. A lithium battery of claim 80,wherein said first electrode is a cathode, and said second electrode isan insertion anode.
 120. A lithium battery of claim 119, wherein saidsecond electrode comprises a material selected from the group consistingof metal oxides, metal chalcogenides, carbon, graphite, and mixturesthereof.
 121. A battery comprising: (a) a first electrode comprising anactive material of the formulaLiCo_(0.8)Fe_(0.1)Al_(0.025)Mg_(0.05)PO_(3.975)F_(0.025) (b) a secondelectrode which is a counter-electrode to said first electrode; and (c)an electrolyte comprising (i) an electrolyte salt; (ii) an alkylenecarbonate having a ring size of from 5 to 8 atoms and unsubstituted orsubstituted with lower alkyl on one or more carbon atoms; and (iii) acyclic ester having a ring size of from 4 to 7 atoms, and isunsubstituted or substituted on one or more carbon atoms with a loweralkyl group.
 122. A battery according to claim 120, wherein said firstelectrode is a cathode, said second electrode is an insertion anode,said alkylene ester is ethylene carbonate; said cyclic ester isγ-butyrolactone; the weight ratio of said cyclic ester to said alkylenecarbonate is from about 1:1 to about 5:1; and said electrolyte salt isLiBF₄.